A bubble and a dolphin

[RobertI]

It was a tricky night last night, lots of moisture in the air which quickly turned to dew, then eventually ice! Sky was 'murky'. Unfortunately stacking was not working brilliantly and SL wouldn't stack more than a few exposures at a time - I think this was caused by poor polar alignment - will investigate more and possibly post another topic. The Dolphin Nebula was very tricky, if stacking had been working properly I think I would have got better results by using Ha and stacking a lot more exposures, but sadly not to be. One I would like to try again under better conditions.

Taken with an RC6 at about F4.5 with a Lodestar mono plus filterwheel. Viewed using Starlight Live.

NGC7635 (Bubble nebula) in mono:

NGC7635 in colour:

SH 2-188 (Dolphin Nebula):

[stash_old]

Nice pictures - What make is the RC6 and what reducer (if any)  do you use to get 4.5

Yes a bit icy - my Canon lens iced up after 1 hr while doing some widefield

[RobertI]

Thanks Stash, it’s an Altair Astro RC6 ( the ubiquitous GSO manufactured scope) with a Meade 0.33x reducer with a spacing that gives F4.5; ie: a reduction of x0.5 rather than the x0.33 which should be possible, as I get coma like effects less than this. Just don’t have the time to narrow down the problem so leaving as is for now. Just about thawed out now! ?

[stash_old]

2 hours ago, RobertI said:

Thanks Stash, it’s an Altair Astro RC6 ( the ubiquitous GSO manufactured scope) with a Meade 0.33x reducer with a spacing that gives F4.5; ie: a reduction of x0.5 rather than the x0.33 which should be possible, as I get coma like effects less than this. Just don’t have the time to narrow down the problem so leaving as is for now. Just about thawed out now! ?

Thanks Rob - looked at one of those but AA doesn't do them any more - the AA RC6 came with 2 bars (top/bottom) which I thought was a good idea plus extension tubes. Still at least it was clear !!!!

[RobertI]

1 hour ago, stash_old said:

Thanks Rob - looked at one of those but AA doesn't do them any more - the AA RC6 came with 2 bars (top/bottom) which I thought was a good idea plus extension tubes. Still at least it was clear !!!!

Yes, most other retailers don't have the second bar on the top, apparently makes it more rigid bit also extremely useful for mounting things. I find mine is better to use for EAA than the C8 , mainly for three reasons; the 10:1 lockable crayford is much better to use than the knob of the C8, the fixed mirror doesn't suffer from the the mirror flop and shift of the C8, and it is less prone to dew than the C8. However the massive focus range of the C8 is very useful when switching between reducers and changing effective focal lengths, with the RC6 you have to add remove extension tubes. I will try the C8 again some time as it seems to work well for most people. RC6's seem to come up pretty frequently on the used market for not much money, let me know of you get one!

[Guest]

Nice pictures

[MartinFlower]

Nice pics. I am using an ultrastar with filter wheel. Not had much luck using starlight live tbh and normally dont stack as I use SGpro. I tried using the tutorial that someone did on here using SLL and narrowband but i must have missed something as it didnt really work out for me.

how did you get the second pic using this method?

 

 

[RobertI]

1 hour ago, MartinFlower said:

Nice pics. I am using an ultrastar with filter wheel. Not had much luck using starlight live tbh and normally dont stack as I use SGpro. I tried using the tutorial that someone did on here using SLL and narrowband but i must have missed something as it didnt really work out for me.

how did you get the second pic using this method?

 

 

Thanks Martin. The second image is colour only I think (no narrowband such as Ha, only RGB filters). From memory I think I did the following (note that I am using a Xagyl filter wheel so not using the SL filter wheel feature):

On the exposure tab I selected the red channel, set the filter wheel to red filter and took 3x30 second exposures - the display showed a faint red image which can be adjusted. I then selected the green channel (remembering to untick the red channel), set the filter wheel to green and took 3x30 second exposures - the display now shows brighter yellowish image. I did the same for green and the image suddenly came to life with full colour. 

The colour images are fainter than the monochrome images (for which I use a luminance filter), I tried to combine the colour and luminance once but the luminance completely washed out the colour, I'm sure there is a way of dealing with this but I haven't attempted this yet. 

I also find the colour is shows gradients more. Overall I actually prefer the monochrome images for detail and contrast.