C925/Vixen GP session

[Stu]

A few thoughts on the kit I used and my session last night, the first reasonable one I've had with the C925.

This C925 was a problem child, which I am currently fostering and am hoping for full adoption when funds allow. When received, the main problem with it was that the secondary support was loose, but also jammed so that it could not be removed to sort it. The corrector plate was also in quite a mess, with dewspots and multiple snail trails (I think they had been using it as a race track!) I had to remove the corrector plate, and after multiple attempts, finally managed to remove the secondary support by using a hairdryer and a pair of rubber gloves to grip it!

The corrector took alot of work. Washing in warm soapy water, Baader Wonderfluid, all tried with multiple applications and would not shift the snail trails. Finally, I resorted to good old fashioned saliva. My apologies if you find this gross (it was!) but plentiful applications of said cleaner and the corrector was transformed. There are still minor traces, but basically it looks pretty good now. Some cleaning up of the threads on the secondary support and this then screwed tightly onto the corrector and all was well. I re-assembled it making sure the corrector was aligned with the marks.

Collimation took a while. I started by using an artificial star down at the end of the garden. This got me close, but I needed a proper star test on Polaris to get it better. I'm still not totally happy with it, and will spend some more time on it soon. I've left the screws in rather than switching to bob's knobs as I feel it is more likely to keep collimation with the original screws.

Mount wise, I have my Vixen GP mount, which I advertised and withdrew as I realised I really like it! Fitted with iOptron Goto kit, it works very well, syncs with SkySafari via SkyFi and has a pretty fast slew rate. The only issue is that it is quite noisy. I've mounted it on an EQ6 Tripod, with a 16" and 8" pillar bolted together to get me height without the tripod legs getting in the way too much. Height is needed to give me reasonable views over the hedge and fencing surrounding my observing site. I would say the GP copes but is getting towards it's limits. It helps that I have a Meade autofocuser fitted so for fine focusing I do not need to touch the scope. I also have a heated AstroZap dewshield which I did not use last night (no dew), but certainly will in future.

In the C925 last night, I used a WO Diagonal fitted with a PowerSwitch and a filter slide made by Earthwin. This allowed me to use a Barlow or Reducer, plus gave me the ability to switch in UHC or OIII filters as required. The beauty of the SCT is that there is plenty of back focus for this kit. I'm not convinced by the quality of the diagonal itself, so at some point will convert this to work with T2 fittings so I can use my Zeiss Prism or BBHS Sitall mirror diagonal.

In the spirit of @iPeace in terms of DIY projects, I used my 80mm Megafinder/TelRad combo, which generally worked well. It is awkward when the TeRad ends up underneath the finder, but still workable. Not sure I can justify fitting two TelRads, so might pop a Rigel on the other side to make the ultimate finder system 

So, that's the kit. Last night I did not align the mount very well, so the Goto wasn't particularly accurate, but I was always able to find things with the TelRad and then the finder. As a finder eyepiece in the C925, I used a 40mm TMB Paragon, giving x59, 1.1 degrees fov and a 4mm exit pupil. It worked surprisingly well under my rubbish skies which were around mag 4.5 NELM last night.

The Veil revealed itself quite nicely with the OIII filter, probably my best view of it from home. The part of the Witch's Broom running through 52 Cygni was clear, extending significantly with averted vision, although the broom itself faded out even with AV. Panning a surprisingly long way across to the Eastern Veil, I was pleased to see the two 'hooks' at the bottom of the arc, something I've only seen from dark sites before. I was however troubled by an annoying reflection which I need to identify and fix though. with 52 cygni just outside the field, two arcs of light showed across the whole fov. as the star was brought into the fov, they tightened then disappeared. I guess I can try either the dew shield, or flocking the interior to remove this? I need to check whether it is related to using the filters or not.

M13 was nicely resolved, but actually crying out for some darker sky; the resolution was there, but it just wasn't punching through the LP. I could really see that at higher power it will be a tremendous sight under a good sky. The propeller was not visible as such, but I could certainly see signs of it in terms of a couple of visible lanes.

M92 looked surprisingly bright, and I also caught NGC 6229, a new one for me.

Just a tour of regulars from then on to test things out. M57, nicer with UHC, and better still with the OIII which blackened the sky and gave lovely contrast. With an 18mm BGO in the scope, the Ring was beautifully defined. M27 likewise.

Vega showed cleanly as you would expect, with the tiny secondary clearly visible. The Double Double resolved at x130 with the 18mm BGO. I STILL prefer the view through my Tak, star shapes just so much cleaner, but the benefits of the C925 lie elsewhere and I can see those coming through. Between the Double Double, I could see two additional stars which @chiltonstar picked out in his Mak 180 at mag 11.94 and 12.68, but could not see the two fainter ones at mag 13.52 or 13.93. That must presumably be down to sky brightness and conditions.

M31 was its usual large grey blob, just larger and brighter than with the Tak. M32 clear but M110 elusive, due to its much lower surface brightness.

Finally I tried for NGC457, my old favourite and it did not disappoint. Nicely framed in the 40mm. One thing I am noticing now, unfortunately, is the astigmatism in my eyes. It's not something which has troubled me before, but with longer focal length eyepieces it is certainly visible now unfortunately so it may be something I need to find a solution to quite soon. Contacts may be the answer as i really don't want to have to start wearing glasses to observe.

So, that's it. Just a little bedding in session really. I hope to get this scope to SGL12, along with one other addition I have planned.

The C925 I intend to mod quite heavily. I will certainly flock it, but will also look at a cooling mod to see whether I can improve the star shapes further. Not totally convinced by my 16+8" pillar, I might drop it back to just the 16" for better stability.

I'm presently in two minds about the C925. It is potentially a lovely scope, and surprisingly compact for the aperture, but the C8 Edge I had was much more compact, lighter and not so far behind in terms of DSO performance. My intended use for the 925 would be portable aperture, so it remains to be seen if it fills this requirement in a way which means it actually gets lots of use, vs being just that bit too big. Time will tell, but I hope it fits in just fine  

I shall post some pictures when I get the chance to take some.

 

[iPeace]

I did have an eye on your Vixen GP. A beady one. Two eyes, actually. Love the color, value the quality. EQ just not my thing.

Great write up, excellent pics!

[Stu]

43 minutes ago, iPeace said:

I did have an eye on your Vixen GP. A beady one. Two eyes, actually. Love the color, value the quality. EQ just not my thing.

Great write up, excellent pics!

Mike, I think you might be a very strong candidate for iOptron AZ Pro Goto. Looks pretty good, built in battery so no external cables and sets itself up pretty easily I think. Handy for finding things aswell as tracking them once found.

[iPeace]

17 minutes ago, Stu said:

Mike, I think you might be a very strong candidate for iOptron AZ Pro Goto. Looks pretty good, built in battery so no external cables and sets itself up pretty easily I think. Handy for finding things aswell as tracking them once found.

All very well, but what color is it?

For the moment, I'm enjoying the unmotorized, go-to-less approach a lot. I have the setup tuned and my workflow is getting ever more efficient and I am finding more and more. That is another reason I held back on the GP - the seemingly excellent motor drive would have been wasted on my cro-magnon sensibility.

It is a thing of beauty, but it would be a crime to remove the drive just to give me a solid, beautifully green colored, manual slow-motion control option for use at high magnification. Besides, I had a feeling you'd want to keep it anyway.

I won't say 'never', but the appeal of doing without motors or go-to is great indeed.

[Stu]

Just now, iPeace said:

All very well, but what color is it?

For the moment, I'm enjoying the unmotorized, go-to-less approach a lot. I have the setup tuned and my workflow is getting ever more efficient and I am finding more and more. That is another reason I held back on the GP - the seemingly excellent motor drive would have been wasted on my cro-magnon sensibility.

It is a thing of beauty, but it would be a crime to remove the drive just to give me a solid, beautifully green colored, manual slow-motion control option for use at high magnification. Besides, I had a feeling you'd want to keep it anyway.

I won't say 'never', but the appeal of doing without motors or go-to is great indeed.

Actually Mike I have two Vixen GP mounts. One has the iOptron GOTO fitted, and the other just has simple dual axis MT1 motors with a hand controller and sits on a nice wooden tripod. The motors don't slew very fast (x32 max), but are very smooth and quiet. If I'm just using the Tak on the Sun or planets, then I use this mount. It tracks very nicely, and silently, is very simple to setup and relaxing to use. Yes it needs power, but I just use a Tracer battery which is lightweight and no hassle. 

Having tracking really helps you concentrate on the target without nudging (or tweaking a slo mo control). It's worth trying at some point.

[Chris]

Hey Stu, I really enjoyed your report  I'll have to remember the saliva thing for stubborn optical stains  Good work getting the scope back into shape, it sounds like it's got some potential.

I've not owned a scope above 8", but even so I think you have a point about the C8 Edge...hands down it's the best scope I've had the pleasure of owning (compact, sharp, flat of course, and you can squeeze 1.4 degrees out of it!).

I've heard that flocking SCT's doesn't work, but I hope this is wrong? I can't see how it would be different to flocking a Newt and plenty do that. I've reliably heard a number of times that a .63 reducer makes stars tighter. Might be worth looking into although you did mention a reducer I'm sure, in which case I'd be interested to hear your view? 

The mount looks nice, I've heard good things about the Ioptron goto system, I especially like the polar allignment routine,

[chiltonstar]

Looks good Stu!

All that's needed now to complete the kit is a clear, dry Autumn.....

Chris

[Stu]

2 hours ago, Chris Lock said:

Hey Stu, I really enjoyed your report  I'll have to remember the saliva thing for stubborn optical stains  Good work getting the scope back into shape, it sounds like it's got some potential.

I've not owned a scope above 8", but even so I think you have a point about the C8 Edge...hands down it's the best scope I've had the pleasure of owning (compact, sharp, flat of course, and you can squeeze 1.4 degrees out of it!).

I've heard that flocking SCT's doesn't work, but I hope this is wrong? I can't see how it would be different to flocking a Newt and plenty do that. I've reliably heard a number of times that a .63 reducer makes stars tighter. Might be worth looking into although you did mention a reducer I'm sure, in which case I'd be interested to hear your view? 

The mount looks nice, I've heard good things about the Ioptron goto system, I especially like the polar allignment routine,

Thanks Chris! Glad you enjoyed it  

Perhaps when the money starts to flow again I can have a C8 Edge aswell  

I did mention a reducer (in the PowerSwitch), but actually I didn't use it last night. Will try it out next time.

I do like the mount. It's very capable but still lightweight and easy to handle. I haven't really explored the Goto system very much, must find out more about its functions.

[Stu]

23 minutes ago, chiltonstar said:

Looks good Stu!

All that's needed now to complete the kit is a clear, dry Autumn.....

Chris

Thanks Chris.

Absolutely right! Please let's have some decent conditions this Autumn!!

[Stu]

Just had another nice little session with this kit. Had a few problems to start with; my iOptron GOTO converted itself into an iOptron 'Get somewhere vaguely in the right direction but not that close'! Some investigation showed that the motor drive gears had come lose on one of the axes. Tightening with an Allen key sorted that, so we were back to full GOTO once more!

The main thing I tried tonight was the binoviewers. These are Baader Zeiss Mark IVs, with a GPC fitted (still can't remember which one!) The 925 being an SCT, I had no problems obtaining focus either just with the GPC, or using either the reducer or multiplier in the PowerSwitch. It's a bit of a pain winding the focus in and out so far, so I didn't change around too much once I found the best option for each target, but still easier than swapping a Barlow in and out.

M13 for instance took higher power with the multiplier selected, whereas M27 looked best with the reducer and OIII filter slid into the light path. Both targets looked lovely, sparkling resolved stars in M13 complete with propeller, and plenty of detail in M27 including the outer shells of gas, not something I normally see; the transparency was better tonight.

M92, M15, M2 and NGC6934 were all caught tonight. Really enjoyed M92 again, at high power it had plenty to offer. I've not been a fan till now, often overlooking it in favour of M13, unfairly now it seems. The DC also looked great, and surprisingly both clusters fitted into the fov of the 40mm TMB, which is proving a very handy ep in this scope.

I also fitted the dewshield to try to fix the glare issue I had. This certainly improved matters, cutting down the reflections seen but not eliminating them completely. Perhaps flocking is needed after all?

Anyway, progress made, and I'm enjoying the setup, so let's bring on those clear autumn skies!

[cotterless45]

Brilliant Stu ! Just love custom and rescued gear being well used. Sounds like you've been keeping some good skies down there ! That rig's going to excel under dark skies. I prefer quite a few globulars to M13 , even the more delicate ones pick up well under some darkness,

Nick.

[Commanderfish]

Hi Stu,

Did you have no dew shield on at all?  That's amazing!  

You might find that the reflections dissappear with the dew shield on.  I used to get reflections something like that when my dew shield fell off the OTA. Given that almost all year you'll need the dewshield, I'm not sure you need to flock...