Vixen Mounts

[andrew2008]

Currently looking for a GEM for mostly visual use and start doing some AP. Looking at the Vixens as i've had experience with an EQ6pro and I don't really consider it to be portable. Then the Heq5 is still quite heavy and for around a $1000 more i could have a Sphinx SXW or GPD2 which by all reports are much better mounts and still very portable. Will probably be looking at it to hold a VMC200l with 6.3 focal reducer and an ED80. Using a DSLR for photos.

Would either the VMC200 or ED80 with a guidescope piggybacked be too much weight?

Could anyone with experience give an estimate on how long the subs could be taken on the Vixen mounts without quiding? Length of subs on HEQ5 without being guided?

How user friendly is the Starbook hand controller?

[Terry B]

I previously owned a GP mount with a SS2000 to cary my Vc200l.
This was adequate for visual and 30 sec exposure CCD images bit not adequate to carry a guide scope. The GPDX is much heavier than the GP but still would be pushing it for 2 scopes.

[Ian Robinson]

Why not use an OAG rather than a guidescope with the VMC200.

A Lumicon 1.25" Newtonian Esyguider would do the trick and will :
- eliminate guiding errors due to guidescope mount flexure
- cut down on the load on the GEM
- eliminate the need for a separate guidescope and the extra expenses needed to mount the guidescope piggyback or sidebyside style (expensive).

From what I've read, a GP with dual axis drives , or even better a Starbook (has facility to plug in an autoguider) is a capable astroimaging platform , so is a Sphinx (SX) and a Sphinx Delux (SXD) is even better (has a very good loading capacity) , A GPDX (now called a GPD2) is even better and can bought with a Starbook upgrade.

Check out http://www.vixenoptics.com/PDF/tele%20catalog2.pdf for more info and to see Vixen Partology.

Check out http://www.lumicon.com/telescope-accessories-list.php?cid=59&cn=Newtonian%2FRefractor+Easy+Guide rs for info on Lumicon's 1.25" esyguider system.
The very low profile of these is a huge plus.

You'll need to guide (at manually least using an illuminated recticle eyepiece) to get good images with your telescope at prime focus.
If you are using wide angle lenses or telephotos , the subs you can do unguided will depend on the focal length of the camera lens used , your mounts PE and how well you've nailed your polar alignment and how good tripod or pier leveling is.

IMO if it's a choice between VMC200 or ED80 , I'd opt for the VMC200 , it's a much more capable telescope.

[JohnH]

Regarding the Sphinx range for AP purposes - do not do it.

Check out the Yahoo group for more information but in my case the DEC backlash on the mount was so high (>>10s) that it made it almost unusable for AP with a VC200L which is F9 (fl 1800) the VMC200L at fl1950mm is even worse!.

You might want to go for the ED80 as a guidescope and it can then serve double duty as a wide field imager but now you are going to need rings (8" rings are heavy) and/or adapter plates/dovetails - you will surely overload an SXW or GP, you might get away with a SXD or GPD but I doubt it.

It is possible the GPD/Starbook/OAG combination might work for you but the general advice is to go for plenty of overhead in carrying capacity where AP is concerned so an EQ6 pro might well be a better bet.

You mention portability as an issue and that is why I went for the SXW originally and it surely is a capable and portable mount and great for visual or widefiel imaging use - so if the ED80 or VMC alone is your choice you can probably use the Lumicon OAG suggested (I have this unit now and love it!) and have a good and productive time. If you go for the VC200L/guidescope combo however you should think about a higher rated mount, have you considered the G8?

[Wavytone]

Andrew the Vixen SXW is primarily a visual mount, it can be pressed into duty for short focal length astrophotography with the small, fast refractors up to 80 or maybe 100mm aperture. It is not suitable for long exposure astrophotography at focal lengths > 700 mm.

If you want to do AP don't go in cheap hoping to upgrade, all you will do is spend about double what it will cost if you face the real cost and buy a decent setup from the outset. If you aren't prepared to plunge $10k and possibly $20k on it, don't start.

There is an old rule which IMHO still holds - the diameter of the worm wheels must be at least half the aperture of the scope. Otherwise your mount will be inadequate. The SXW is little more than a fancy toy in this respect and the EQ6 no better. The GM11 is a start, but only adequate.

If you are serious the starting point for a VC200L is a mount from Astrophysics http://www.astro-physics.com/ or better.

The reason I stay clear of it is that there are so many with more time in dark skies that I may as well not bother, and wait till they post their shots on the net.

[andrew2008]

Thanks for the advice so far.

I have seen plenty of photos taken on systems worth half the 10K you suggest wavy and some probably less. If i get half as good as some people with the modest gear that post their images on the site i'll be very happy. Not looking to win any awards here just have some fun with a hobby i love.

Well unless i can find a 2nd hand vixen i'll just be happy with a HEQ5 and do widefield with an ED80 and spend the extra $1000 or so on and ST80 and guider.

[CometGuy]

Andrew,

A C8 at 2000mm unguided subs up to 45 seconds are OK with good polar alignment with my Sphinx SXW, provided you can tolerate throwing 20% of the frames. Here is an example of M4 with 15 x 45 second UNGUIDED exposures (with QHY9) reproduced at a scale of 0.5" per pixel.

What Wavytone says about the Sphinx is problably right, but I can't really comment personally on using autoguiding.

Terry

[bobsastro]

Dear Andrew,

Not sure whether you are still looking for a VC200L and GPD2 with Skysensor and guiding, but noticed your post in a search and have just listed that very combination under Telescopes in the classified area.

Best Regards,
Bob

[hotspur]

The Vixen GP mount I own gives very good result,unguided-up to 3 minutes.
My new Vixen GPD2 also is very good,with guiding.

The Vixen Sphinx is not good for AP,a friend has one,but uses it mainly for visual-not recommended for AP.the star book is also not the best for AP.Its a shame Vixen no longer have the SS2K for sale,I picked up a 2nd hand one and put it on the GPD2,its very useful,and seems to be built to a finer standard to the 'Skywatcher' gear.

C