best goto type mount for SPC8?

Hi folks,

I've been tossing around the idea of putting my semi-ancient, black
tube Super Polaris C8 on a goto-type mount from either Celestron,
Meade or some 3rd party product (are those compatible, anyway?).

I wonder if anybody in SAA has done something similar and I'd be most
happy if you could share your experiences, price tags, what-not-to-buy
and so on.

All the best & thanks in advance,

uwe



--
GPG Fingerprint: 2E 13 20 22 9A 3F 63 7F 67 6F E9 B1 A8 36 A4 61

"Uwe Schürkamp" wrote in message
...
Hi folks,

I've been tossing around the idea of putting my semi-ancient, black
tube Super Polaris C8 on a goto-type mount from either Celestron,
Meade or some 3rd party product (are those compatible, anyway?).

I wonder if anybody in SAA has done something similar and I'd be most
happy if you could share your experiences, price tags, what-not-to-buy
and so on.

All the best & thanks in advance,

uwe
'Best', covers a lot of ground. :-)
Many of the people here, will have moved tubes like this, onto a variety
of mounts, ranging from cut down 'cheapies', through better units, and
including such things as making their methods of supplying goto if wanted.
With suitable rings, and/or dovetail rails, you can mount ust about
anything, on just about anything.
In general, there are a number of 'classes' of stuff around to do this.
The first are the mounts like the CG5, from Celestron. These are all
'clones', of earlier mounts, with a number of modifications, and different
models achieving different levels of success. The 'original' version in
this case, has been improved by using ball races in the main shaft, and on
the latest variants, on the worm shaft as well, and in a good example, can
give very reasonable results. The early versions, also had a pretty poor
tripod, which has now been upgraded to a very useable unit. Meade had
their LXD55 (which has a _lot_ of problems), and more recently, their
LXD75, which is pretty much a match for the CG5 (the two are 'nip and
tuck', with some features better on one, and other better on the other).
Then there is the 'real' original mount, the Vixen GP-DX. This is a superb
mount, with better PE than the clones (this is down to things like using
brass gears, instead of a fairly porous cast steel). However in the US,
the 'best' goto controller (the Vixen SS2K), is not normally available,
because it has not passed your FCC tests. One user on here recently, had a
GP-DX, and picked up the Celestron CG5-GT, on AstroMart, then moved the
motor assemblies from the latter onto the Vixen mount, selling the bare
CG5, to give a modern GOTO system, on a great mount. An 'interesting'
idea, but it was only really 'economic', because he already had half the
system. At the same sort of 'scale', there is the Losmandy GM8. In the
past, the GP-DX, 'beat' this on PE performance, but a couple of years ago,
the manufacturing process used for the worm gears was updated, and these
units, now have nice PE. Vixen also have their 'Sphinx' system, which is a
nice 'gadget', but 'good in parts'. The motion basically, is good, but
there is no software PEC correction. Only recently, have they got the
autoguiding to work (this is a charged for upgrade to the software). The
backlighting on the display, and the polar scope, are both too bright,
with the latter improved a little on the latest software, but the former,
and 'inherent' fault, in the technology chosen, and requiring the addition
of a ND filter to dim the display to reasonable levels. It has the
feeling, that the basic mount was designed by astronomers, but the
software, was 'farmed out' to a sub-contractor, who does not really
understand what is needed.
Remember if you might want to go heavier latter, provided you do not mind
the weight, a 'heavier' mount, is always 'better', with things like the
HEQ5 (this only a little), the EQ6, and the G11, with their corresponding
GOTO controllers bing capable of supporting more weight.
Take your time. Don't be afraid of 'second hand'. If you have a local
astronomy club, you may be able to see different mounts, and get an idea
of how well they work.
Now that having been said, the 'best' mount, would be a complete overkill.
I have put a scope this size, on an AP900, and with this, the tracking
'runs rings' round anything offered by the cheaper mounts, but
unfortunately, 'at a price'...

Best Wishes

On Tue, 08 Feb 2005 11:44:14 GMT, Roger Hamlett wrote:

"Uwe Schürkamp" wrote in message
...
Hi folks,

I've been tossing around the idea of putting my semi-ancient, black
tube Super Polaris C8 on a goto-type mount from either Celestron,
Meade or some 3rd party product (are those compatible, anyway?).

I wonder if anybody in SAA has done something similar and I'd be most
happy if you could share your experiences, price tags, what-not-to-buy
and so on.

All the best & thanks in advance,

uwe
'Best', covers a lot of ground. :-)

Hi Roger,

thanks much for your thorough and very detailed reply. The Losmandy
thingy sounds interested. I have two left hands so disassembling one
mount to put together another probably is out of the question for me
;-) That said the SPC8 mount has gears for RA / DEC motors, but I'm
really interested in the GOTO feature to save precious observing time
spent "simply" searching for the object I want to observe.

All the best & thanks again,

uwe


--
GPG Fingerprint: 2E 13 20 22 9A 3F 63 7F 67 6F E9 B1 A8 36 A4 61

Uwe Schürkamp wrote:
On Tue, 08 Feb 2005 11:44:14 GMT, Roger Hamlett wrote:

"Uwe Schürkamp" wrote in message
...
Hi folks,

I've been tossing around the idea of putting my semi-ancient, black
tube Super Polaris C8 on a goto-type mount from either Celestron,
Meade or some 3rd party product (are those compatible, anyway?).

I wonder if anybody in SAA has done something similar and I'd be
most happy if you could share your experiences, price tags,
what-not-to-buy and so on.

All the best & thanks in advance,

uwe
'Best', covers a lot of ground. :-)

Hi Roger,

thanks much for your thorough and very detailed reply. The Losmandy
thingy sounds interested. I have two left hands so disassembling one
mount to put together another probably is out of the question for me
;-) That said the SPC8 mount has gears for RA / DEC motors, but I'm
really interested in the GOTO feature to save precious observing time
spent "simply" searching for the object I want to observe.

I have an SP and it is not a bad mount at all (I also have used a C8 on it).

You can make it a GOTO mount in several ways, one way is to do like I did:
- A pair of Astromeccanica AM-V motors
http://www.astromeccanica.it/motor.htm
- A Boxdoerfer MTS-3SDI controller http://www.boxdoerfer.de/
- ... and http://arnholm.org/astro/software/mtsca/

--
Carsten A. Arnholm
http://arnholm.org/
N59.776 E10.457

Don't be afraid of 'second hand'.

:)

I understand how you mean this phrase but in light of the excellent
information that you offer in your message, how can an user not be?

You may not realize it but the discussion you just wrote represents the
collective experience (and considerable expense) of many people gaining
this information by trial and error.

For a single amateur to learn this by the same method is unrealistic.

When you are buying anything secondhand, require return privileges if
the item does not meet your needs. In the cases where this is not
possible, only spend as much money as you can afford to lose. In my
opinion, many of the mounts one sees being sold on Astromart are there
because the owners are dumping their problems on their fellow amateurs.

Another example....

After being away from the hobby for some time, I am just amazed that
the amateur astronomer community still tolerates mounts that supposely
offer PEC but don't work as advertised. Inexcusable in my opinion. With
the ability to communicate in discussion groups like these so a
detailed review of any product would get widespread readership,
manufacturers should have a very strong motivation to get the product
right the first time.

TMT

"Too_Many_Tools" wrote in message
oups.com...
Don't be afraid of 'second hand'.

:)

I understand how you mean this phrase but in light of the excellent
information that you offer in your message, how can an user not be?

You may not realize it but the discussion you just wrote represents the
collective experience (and considerable expense) of many people gaining
this information by trial and error.

For a single amateur to learn this by the same method is unrealistic.
What I posted, was based entirely on my _own_ experiences.

When you are buying anything secondhand, require return privileges if
the item does not meet your needs. In the cases where this is not
possible, only spend as much money as you can afford to lose. In my
opinion, many of the mounts one sees being sold on Astromart are there
because the owners are dumping their problems on their fellow amateurs.
If this is true of 'AstroMart', it is sad. However many users upgrade. I
went through a CG5, then a GP-DX, then a G11, then a AP900, and have had
several other mounts 'in passing'. The old mounts were never 'problems',
but had to be replaced as the scopes I used, got heavier, and my own
requirements increased. They were sold through the UK astronomy adverts,
and I believe, both buyer, and seller got what they wanted. The AP900, was
bought this way, as were quite a few other items, so I have experienced
the transactions from 'both sides of the fence'.

Another example....

After being away from the hobby for some time, I am just amazed that
the amateur astronomer community still tolerates mounts that supposely
offer PEC but don't work as advertised. Inexcusable in my opinion. With
the ability to communicate in discussion groups like these so a
detailed review of any product would get widespread readership,
manufacturers should have a very strong motivation to get the product
right the first time.
This is why seeing the mounts 'in use' is so important. Astronomy clubs,
can allow you not only to see the advantages and disadvantages of
particular units, but also to possibly buy a 'known' unit, with a history
verifyable by the other members, for a lot less than the 'new' price.

Best Wishes

Hi Roger,

On the details that you supplied, I am very impressed. It shows a good
understanding of the problems in mounts and over a number of product
lines and production releases.

It is also next to impossible for the average amateur to have that
exposure...consider the total outlay in dollars and time alone much
less the experienced eye that it takes to determine the good from the
bad.

I think we both know that when a mount is found lacking, it starts
showing up in droves on the used market. The same process that works
for undesirable cars works for scopes as well.

I agree that the best person to buy something from is one committed to
the hobby who is truly upgrading to the next level. Reality is that
there are usually people standing in line to buy from that person and
the rank amateur has little chance of being the first one in that line.

TMT

On Tue, 08 Feb 2005 11:44:14 GMT, "Roger Hamlett"
wrote:

Vixen also have their 'Sphinx' system, which is a
nice 'gadget', but 'good in parts'. The motion basically, is good, but
there is no software PEC correction.

True, it would be nice to have, but is not necessarily a necessity.
There are indications the tracking may be good enough without PEC for
short focal lengths (1000mm) in Build 26.

Here's a single *unguided* 250 sec exposure I took this weekend:

http://gamesforone.com/stars/images/b33.jpg

Does the PEC really work on the lower cost Celestron and Meade mounts?

Only recently, have they got the
autoguiding to work (this is a charged for upgrade to the software).

$20. Not a serious cost issue here.

The
backlighting on the display, and the polar scope, are both too bright,
with the latter improved a little on the latest software, but the former,
and 'inherent' fault, in the technology chosen, and requiring the addition
of a ND filter to dim the display to reasonable levels.

Overblown. The ND filter works ok and Build 26 now has a timer feature
whereby the display turns completely off after a user-adjustable time
period. If you use the ASCOM driver for remote control, the backlight
never even comes on.

It has the
feeling, that the basic mount was designed by astronomers, but the
software, was 'farmed out' to a sub-contractor, who does not really
understand what is needed.

Nah, it is just different than the Nexstar and Autostar hand paddles.
I am starting to really like my Sphinx now that the problems seemed to
be corrected. With the ASCOM driver, you can control it with any
ASCOM-compatible software program. I use SkyMap Pro. Plus the scope is
driven by ASCOM through an Ethernet port -- a step up for those that
use laptops for remote control.

Theoretically, you should be able to autoguide over the Ethernet port
using the PulseGuide commands available in ASCOM. I am currently
working on getting GuideDog setup to do so.

The Sphinx deserves a more serious look.

---
Michael McCulloch

"Michael McCulloch" wrote in message
...
On Tue, 08 Feb 2005 11:44:14 GMT, "Roger Hamlett"
wrote:

Vixen also have their 'Sphinx' system, which is a
nice 'gadget', but 'good in parts'. The motion basically, is good, but
there is no software PEC correction.

True, it would be nice to have, but is not necessarily a necessity.
There are indications the tracking may be good enough without PEC for
short focal lengths (1000mm) in Build 26.

Here's a single *unguided* 250 sec exposure I took this weekend:

http://gamesforone.com/stars/images/b33.jpg

Does the PEC really work on the lower cost Celestron and Meade mounts?

Only recently, have they got the
autoguiding to work (this is a charged for upgrade to the software).

$20. Not a serious cost issue here.
I agree, except that when the mount was originally marketted, there was no
suggestion that it would be charged for. In fact a couple of the early
advertisements, were phrased to say that it would be free. It was a little
'naughty' by the marketting department...

The
backlighting on the display, and the polar scope, are both too bright,
with the latter improved a little on the latest software, but the
former,
and 'inherent' fault, in the technology chosen, and requiring the
addition
of a ND filter to dim the display to reasonable levels.

Overblown. The ND filter works ok and Build 26 now has a timer feature
whereby the display turns completely off after a user-adjustable time
period. If you use the ASCOM driver for remote control, the backlight
never even comes on.
I still find the display annoying. There is no illumination to the
buttons, which are too sensitive to be comfortable in the cold with gloves
on. So have ended up with a ND filter, in a custom made 'case', which has
the buttons recessed, with rings round them, so you can feel them in the
dark. Compared to the used interface quality of the SS2K, it is not even
in the same 'class', and it is wrong that the unit should need an add-on
filter to work acceptably. Turning the display off, doesn't help if you
have already destroyed your night vision...

It has the
feeling, that the basic mount was designed by astronomers, but the
software, was 'farmed out' to a sub-contractor, who does not really
understand what is needed.

Nah, it is just different than the Nexstar and Autostar hand paddles.
I am starting to really like my Sphinx now that the problems seemed to
be corrected. With the ASCOM driver, you can control it with any
ASCOM-compatible software program. I use SkyMap Pro. Plus the scope is
driven by ASCOM through an Ethernet port -- a step up for those that
use laptops for remote control.
Yes. This is one part I really 'like', except that the interface should be
going to the scope mount, and not to the hand controller. If you are using
guiding, you have the main cable, autoguider cable, and ethernet cable all
routed to the hand controller. I can understand 'why', but it does not
make it 'nice'.

Theoretically, you should be able to autoguide over the Ethernet port
using the PulseGuide commands available in ASCOM. I am currently
working on getting GuideDog setup to do so.

The Sphinx deserves a more serious look.
Yes, it is a good mount now, if you can live with the remaining problems,
but it should have been 'excellent' from day one. On the display for
example, the brightness is because they went for EL backlighting. This is
the commonest solution for laptop displays etc., However you can get the
same displays with LED backlighting, which gives a slightly less smooth
backlight, but can be dimmed to nothing. Also there are other display
'versions' available, including the transflective forms. These have the
advantage of being visible in daylight, without depending on the backlight
(these are suddenly taking off in the phones and similar devices). This
sort of display combination, is an 'off the shelf' answer from many
suppliers, and would have given a display that could be seen in the
daytime, when solar imaging, and be as dim as needed at night. I have been
involved with a couple of systems using this type of display, and they
would have been a far better choice.
I think I am spot on, in my assesment, that the handcontroller was 'farmed
out' to a team outside the company, who are not involved in astromony, it
explains exactly why a system that is in places truly excellent, is marred
in this area.

Best Wishes

On Tue, 08 Feb 2005 22:34:42 GMT, "Roger Hamlett"
wrote:

I still find the display annoying. There is no illumination to the
buttons, which are too sensitive to be comfortable in the cold with gloves
on.

I guess, but I seem to do fine with them. One Celestron Nexstar hand
paddle I had started developing sticking keys with two years. So far,
the Sphinx buttons appear to be able to take the abuse. Perhaps you
should try thinner gloves that give you more feel?

So have ended up with a ND filter, in a custom made 'case', which has
the buttons recessed, with rings round them, so you can feel them in the
dark. Compared to the used interface quality of the SS2K, it is not even
in the same 'class', and it is wrong that the unit should need an add-on
filter to work acceptably. Turning the display off, doesn't help if you
have already destroyed your night vision...

Sounds a bit like you've decided this is a problem whether it is or
not. I find that *any light* destroys your night vision temporarily --
the question being how quickly it recovers. Mine seems to recover
quickly when using the StarBook with a ND filter, plus I have my unit
set for a short timeout and the backlight disappears entirely in short
order. I usually want to observe objects for at least 5 minutes and I
have not found my night vision severely impacted by the StarBook with
the ND filter since I obtained Build 26 with the timed OFF feature.

Yes, it is a good mount now, if you can live with the remaining problems,
but it should have been 'excellent' from day one.

I don't know of any remaining "problems" in Build 26. Missing features
perhaps that would be nice add-ons, but the features that are there
seem to work fine to me. Regarding PEC, are you attempting autoguided
astrophotography and find the Sphinx doesn't perform for you? Or are
you trying to avoid an autoguider entirely?

the brightness is because they went for EL backlighting. This is
the commonest solution for laptop displays etc., However you can get the
same displays with LED backlighting, which gives a slightly less smooth
backlight, but can be dimmed to nothing.

As long as the windows contain white backgrounds I don't think it
matters what kind of backlight you choose. Turning down an LED
backlight to such low levels would just mean you wouldn't be able to
read the display. Having the display at any readable level with white
background will be enough to affect your night vision. Whether it is
EL or LED isn't the issue.

What could be done to best effect would be to have a "night vision"
mode where all is on black backgrounds with shades of red text and
symbols. Then a red filter could be added to further filter the
display backlight without rendering elements on the display
unreadable. I do this with my laptop and it works perfectly.

Plus, aren't EL backlights more power efficient? I prefer longer
battery life. And the more even lighting allows lower overall
brightness levels that still retain full-screen readability.

I think I am spot on, in my assesment, that the handcontroller was 'farmed
out' to a team outside the company, who are not involved in astromony, it
explains exactly why a system that is in places truly excellent, is marred
in this area.

The StarBook is a different paradigm. It has some rough edges, but
after several observing sessions I don't find the model any more
difficult to use than anything else. In fact, even without double star
lists, direct RA/DEC entry, and other features, I find I can still get
the mount quickly to a target.

For example, as I have stated here before, you can find a double star
quickly by using the Constellation object list to get the mount in the
general area, and then use the star chart as feedback to quickly home
in on the target RA/DEC for a faint double star. It works very
efficiently for me. It's as good or better than a LONG linear list of
doubles in a Nexstar or Autostar controller, and it works for every
double rather than just ones pre-picked for you as interesting. Use
the NSOG to pick objects to go after rather than the whims of a hand
paddle programmer...

---
Michael McCulloch