first light - quick N253 with GSO10"RC

[allan gould]

Managed to get a first light image of NGC253 with the new GSO 10" RC scope after getting used to some of its peculiarities as well as getting it properly collimated. Its an LRGB of 80:30:30:30 in 5min subs using the QSI583wsg.
I was mainly interested in its ability to do several things and that was to hold collimation, focus and would it deliver a flat field of stars across the field.
The attached image shows that all is good but I need to accumulate a lot more data to make this image into something with more punch.
The tube is the aluminium version and I found with the fans running and careful focus that star images were excellent and the scope did not reqire re-focusing during the image run.
The focuser is capable of holding the QSI but I think Im going to get a motorised Moonlight focuser for the scope just to add the icing on the cake.

[cventer]

wow that shows a lot of promise.

Very nice.

Did you bin the 583 or run it native ? at 1 x binning it would seem it would oversample but the image looks great.

[jjjnettie]

:) A great start Allan.
"More Data"....our mantra.

[Alchemy]

Off to a good start, but I'd be going longer subs

[gregbradley]

Looks good Allan. Although is that a reflection arc in the image? That arc above the galaxy.

Paul Haese could advise you on that. I think he flocked the tube and secondary mirror shroud.

These GSO RCs are great scopes for the money.

Greg.

[allan gould]

Well picked up Greg
At the moment I'm suffering from internal reflections in the scope that I'm trying to track down. I did a quick shot of the horse head that really shows that despite all the baffles in the scope they don't work that well and that there are a host of internal reflections which also show up in the flats taken with the scope.
I'm thinking that I may have to pull it down and flock and repaint the internals of the scope.
Allan

[allan gould]

The luminance was done at 1x1 while RGB was done at 2x2

Thanks jjj as it does need more data


agreed Clive but I was more interested in a flat field and collimation at this stage. Finessing this scope will take some time as I don't think it's up to the quality of my SCT at this stage - believe it or not.

[peter_4059]

Nice detail Allan. The diffraction spikes also look good.

[RobF]

Looking good Alan. Will be interested to hear about your adventures with this scope.

[madbadgalaxyman]

Must be a really good scope to show the detail in the Silver Coin that is evident in your image.

Relatively shallow is not always bad, when it comes to data, for instance if we want to work out what the centre of a galaxy looks like.

[RickS]

Allan,

That's a very nice first light!

I have the CF RC10 and haven't noticed any reflection issues in the flats (I haven't seen any problems with the lights either, but I don't think I've imaged anything with a bright star in the field yet). I'll have to look more closely.

I'm running at f/6.4 with a focal reducer. I don't have a permanent setup so f/8 is just too slow for me.

I have a FT focuser that came with the scope but I'm about to swap it for an Atlas.

Cheers,
Rick.

[gregbradley]

I believe Paul posted a thread about flocking the inside of the main baffle.
If it is anodised, anodised aluminium reflects heavily in IR.

I am told Blackboard paint is good. There was an excellent thread I read on a Yahoo Group where this guy had researched various matt black paints and come up with the best. Perhaps a google search for telescope matt black paint or similar may pick it up.

Greg.

[sjastro]

Very nice image Alan.

Steven

[ozstronomer]

Nice shot Allan, looks like a good start, just have to sort out the tube reflections and it will be a winner

[allan gould]

Thanks for the comments Peter, Rob and Robert - much appreciated

[allan gould]

Rick, PMed you re the reducer and thanks for the comments

Thanks Greg, it looks as if I may have to strip it all down and redo the matting inside the scope as its that sort of attention to detail that can get the most out of the scope. The gradient in the first post was actually due to my bad as I neglected to do flats for the RGB and only did it for the Lum channel. Too used to melding an OSC and Lum as before. I ran it through PixInsight LE and removed the gradient in the RGB and below is a fixed version. It wasnt meant to be a final shot as I was really looking at the flat field etc and really wanted to show IIS members how it was right out of the box as it were. See the attched image for a correction.





Thanks Steve and Oz. Nice to hear the comments

[madbadgalaxyman]

The way that some of the dust lanes point in the "wrong" direction is shown well in your image, Allan. They point "upwards" from the plane of this galaxy, rather than along it. In other words, they are exiting from the principal plane of NGC 253. For some time, I thought that this was some type of artefact of the way that amateurs process their images, but it is well shown in diverse images processed in different ways.

This is normally the sign of a very actively star forming disk galaxy, in which dust chimneys and streamers are pushed outwards due to energy being put into the ISM by multiple OB stars, supernovae, etc.

Malin, in a study of his unsharp masked images of NGC 253, referred to the "boiling, steaming" interstellar medium of this galaxy.

While there is not a lot of evidence for strong star formation in the large-scale disk and spiral arms of this galaxy, when we look at NGC 253 in infrared imagery, the central burst of star formation (completely hidden in the optical regime), with its gigantic number of OB stars, virtually dominates the light of the entire galaxy!

[trent_julie]

Looking good Allan, I have the RC8 they seem to be a very good range of telescopes

Trent

[DavidTrap]

Great detail Allan - do you give lessons on achieving such detail at these focal lengths?

I notice that you've acquired this scope soon after you bought a VC200L - have you had issues with the Vixen scope, or are you suffering a really bad case of "aperture fever"?

ta
DT

[allan gould]

You are right Robert but it was a shot by Gebany that really turned me on to this galaxy. Just need to get far more data and do it justice

still have some bugs to iron out and will see how I get on with the scope. It's a personal thing with me

[allan gould]

David
Astute of you. I loved the VC200L that I used at Astrofest. Perfectly flat frames across the QHY8 chip at native (2000mm FL) or at f6.4 at reduced FL with the dedicated flattener. Gave me exactly what the Vixen claimed for it. Really nice scope but in the end I realized that I was after something else and so I sold it on. I may wind up like Hagar and regret selling it but I got intrigued by the GSO RC's and thought that I would give them at try.
Actually I've found imaging at 2500fl quite easy and haven't had a problem as long as you pay attention to making the guide scope absolutely rigid. I do it piggy back on a Losmandy rail with the gscope and have been able to do 30 min subs at 2500fl regularly either with my Losmandy or EQ6 mounts.
I have yet to show that the GSO RC is actually better than my 10" SCT.
Aperture fever may eventually strike as I'm really thinking of either a 12" or 14" scope for imaging. Bloody Hough with that Meade scope really had me thinking.
Regards, Allan

[DavidTrap]

Thanks for the reply Allan.

Were you after a smaller field of view, or did you have issues with image quality?

Are you OAG with your QSI? I'm trying my Meade 8 inch SCT with the QSI583. I'm just a bit concerned that at F11 (it plate solves to 2222mm focal length) or F8.5 with a reducer is still a bit slow. The VC200L with a reducer is around that 1250mm sweet-spot focal length.

DT

[allan gould]

David
I thought I wanted something between my 5" apo refractor and the 10" SCT and that was exactly what the VC200L did. It was perfect in that range with excellent image quality. I'm not oag'ing with the QSI as I find that I can't get good stars with any scope I've tried it on. The stars are really out of focus and egg shaped although Nebulosity guides ok on them, but to be honest I prefer a separate guidescope as I always have a guidestar with the DSI Pro and the 72mm WO guidescope. Stars are pinpoint and I'm sure that's why I can guide at 2500mm FL easily
I'm lucky that I'm testing the GSO RC to see if that's what I want or maybe a 12/14" scope.
I had too much "stuff" that I wasn't using and so sold it all off and that has given me enough capital to experiment to see exactly what I want to acquire.
Time will tell, it's all a journey and you read a lot about different equipment but it's only by trying will you know if it's really what you want.
Allan