Bubble Nebula (NGC 7635)

[Erling G-P]

Saw an image of this posted recently and made a mental note of having a go at it, once Cassiopeia is in a more favorable position.

However, a couple of nights ago, I had to abort my galaxy imaging prematurely, as the telescope was about to clash with the tripod legs.  With less than an hour left before dawn, it was too late to start something 'serious'.  Decided to swing the scope to the Bubble Nebula, just to see what I could get, and if there was potential for something on a later date.  What I got looked so promising, so that when the next night the same thing happened - impending leg crash averted in the nick of time, I decided to collect a little more of the Bubble.

Combined the two days to the image attached. 16 + 32 x 3 minute subs, for a total of 144 minutes, or 2.4 hours.  Image is reduced by 50% on each side.  On this size reduced image, Topaz DeNoise AI has an astonishing effect. Original image is quite soft, but Topaz turns it razor sharp!   One effect that may or may not be seen as positive, is that the faintest stars become more visible.  Regrettably the effect isn't quite as profound on a cropped, full size version of the nebula itself, but not the biggest issue, as I think the full field looks better - what a fantastic piece of sky that is!

SW 200PDS w/SW 0.9x CC

SW HEQ5Pro w/Rowan belt mod & ADM saddle

Canon 700Da cooled (-20ºC)

Staraid Revolution autoguider

Darks, flats & bias used

Stacked with DSS.  Processed in AstroArt 6.0.  Denoise & sharpening with Topaz DeNoise AI.

[smr]

Very nice! Lovely colours and detail. Is that the 700Da which was advertised on here a few months ago?

[glafnazur]

That is lovely, I love the star colours and the star cluster top left, is it M52?

[Erling G-P]

Thanks guys, and yes to both questions, at least I think it's M52.   Took a long time before I got any real chance of using the camera, as we've had the same abysmal kind of weather here as in the UK all winter.

[ebdons]

Superb! colours just great, lots of detail as well, well done sir!

[MarkAR]

A very nice bubble.

[steppenwolf]

I really like this image, the colours are wonderful in both the stars and the nebula itself and it has a really 3D effect that I haven't seen before in this object. I note that you have some flare on the really bright stars that you could probably tame with a small ring mask that covers the primary mirror clamps but even this doesn't detract from your beautifully crisp image and ironically, on the bright central star I even think it adds something!

[Erling G-P]

Wow, thanks a lot for those kind words guys!

Steve, regarding the flares, I have been yanking my hair over what causes it.  Pinched optics was suggested by my telescope vendor, but recently someone (you?) posted a solution to the same type of problem with the 130PDS, in the form of a 3D printed ring to cover the mirror clamps.   Noted this with great interest and would like a similar solution, if I could have it scaled up for the 200PDS.  In this image it's tolerable, but the effect really runs away with brighter stars; the Pleiads for example, not to mention Alnitak, when imaging the Horsehead.

[ebdons]

Yes try the ring around the mirror clamps, just a very tiny increase in FR is the result but worth it, I used a pizza base (black) that you put in the oven so is heat proof and that works ok, don't use anything that has a glue or oil base to it as they will leak out. ok all the best Ton

[steppenwolf]

15 hours ago, Erling G-P said:

Noted this with great interest and would like a similar solution, if I could have it scaled up for the 200PDS. 

I have used black cardboard for this in the past, just make sure that you cut a really neat inner annulus to ensure that you don't introduce any different diffraction points! It wasn't me who posted the 3D printer solution (I don't own one - yet!) but the cardboard solution should work very well if you don't have access to anything more sophisticated.

[Erling G-P]

Thanks Steve & ebdons!

I have some rolls of flocking material waiting to be put to good use.  The upcoming summer hiatus might be a good time to do both the flocking and attempt to make a ring for the mirror, as I would most likely have to remove it to do the flocking anyway.

[Waynescave]

On 25/04/2020 at 13:47, ebdons said:

Yes try the ring around the mirror clamps, just a very tiny increase in FR is the result but worth it, I used a pizza base (black) that you put in the oven so is heat proof and that works ok, don't use anything that has a glue or oil base to it as they will leak out. ok all the best Ton

Hi Tony.. This interests me as my dad has a newt and his bad stars have put him off imaging all together at the minute... Would the pizza base method need cutting down to a ring to cover the clamps? Then how is it held in front in position? Many thanks

Wayne

[ollypenrice]

I like the image as well.

The cutting of rings is simplified by a compass-cutter from graphic outlets. For larger diameters you might need to improvise your own.

Olly

 

 

[ebdons]

Hi wayne, yes it held by the clamps against the mirror surface, that's why you need something thick enough the hold itself firm as I only have 3 clamps on my mirror, do a test sample first and then go from there, but needs a very smooth cut inside, I used a very sharp craft knife held against metal cake tin or similar. when done leave the clamps until the ring is perfect and just lightly nip them up. if the clamps are black then the black ring would merge as one with the clamps ok.

[Waynescave]

6 minutes ago, ebdons said:

Hi wayne, yes it held by the clamps against the mirror surface, that's why you need something thick enough the hold itself firm as I only have 3 clamps on my mirror, do a test sample first and then go from there, but needs a very smooth cut inside, I used a very sharp craft knife held against metal cake tin or similar. when done leave the clamps until the ring is perfect and just lightly nip them up. if the clamps are black then the black ring would merge as one with the clamps ok.

Ah I see.. I'll have to help my dad get that sorted.. He'll fall in love with it all again then! 😄