Tulip Nebula Sh2-101 - first HaRGB with the RASA 8

[gorann]

My first HaRGB with the RASA 8. RGB with ASI2600MC (87 x 2 min, gain 100, moonless on 25 August) and Ha with ASI1600MM (61 x 5 min, gain 139, full moon on 31 August). Baader fast Ha 2" filter.

This is a Ha emission region in Cygnus and the Tulip is to the right, and adds to my Sharpless collection. Not sure if the other nebulosity in the image has any designation, but it is quite a lot of it around. There is also some nice dark nebulosity and three intriguing red filamental structures just to the left of the centre of the image. I wonder what they may be.

The RGB image looked rater uniteresting so the Ha collected last night made a big difference.

Edited September 1, 2020 by gorann

[ampleamp]

Nice image Göran and good to see the 1600 getting an airing 👍🏼

[gorann]

11 hours ago, ampleamp said:

Nice image Göran and good to see the 1600 getting an airing 👍🏼

Thanks a lot Alistair. Yes it is now working hard and doing a good job. Finally astrodarkness up here and I had a few clear nights recently.

[ultranova]

What a cracker...you certainly have the rasa tuned in ...nicley captured and processed...

Must be a game changer being able to get all them photons quicker. 

Well done 

Paul

[gorann]

3 hours ago, ultranova said:

What a cracker...you certainly have the rasa tuned in ...nicley captured and processed...

Must be a game changer being able to get all them photons quicker. 

Well done 

Paul

Thanks for you kind words Paul! Yes, at least now when nights still are short it has clearly been a game changer. Now I can get the data for an image in one night, or two nights if I add Ha. I am surprised how well it keeps focus (no refocusing during a night so far) and collimation has been spot on from the factory. Only issue is minor tilt in the cameras - the RASA is apparently very sensitive to this due to the low f-ratio. I can live with it and mostly fix the corner stars it in processing, and it is probably only an issue for me and other pixel peepers.

[alan potts]

Beautiful work, seems you are liking the new camera, your sure using it well Goran.

Alan

[gorann]

4 hours ago, alan potts said:

Beautiful work, seems you are liking the new camera, your sure using it well Goran.

Alan

Thanks Alan! Still at it - may be clear tonight so I aim to such up whatever Ha may reach northern Europe!

[AbsolutelyN]

Another fantastic image Gorann. Wish we had as many clear skies here! Could I ask do you remove the RASA8 optical window for the 1600MM and put it back in for the 2600MC? 

[gorann]

9 minutes ago, AbsolutelyN said:

Another fantastic image Gorann. Wish we had as many clear skies here! Could I ask do you remove the RASA8 optical window for the 1600MM and put it back in for the 2600MC? 

Thanks!

I did remove the optical window since I am using a Ha filter for the ASI1600 (as suggested by both Celestron and Baader). Why should I put it back for the ASI2600 next time I go RGB - does it have any function that you know of?

[AbsolutelyN]

1 minute ago, gorann said:

Thanks!

I did remove the optical window since I am using a Ha filter for the ASI1600 (as suggested by both Celestron and Baader). Why should I put it back for the ASI2600 next time I go RGB - does it have any function that you know of?

I don’t know ... I was wondering if it affects the focus position and is needed to be in place if not using a filter (ie osc). Just curious as planning to try osc on my rasa 

[gorann]

3 hours ago, AbsolutelyN said:

I don’t know ... I was wondering if it affects the focus position and is needed to be in place if not using a filter (ie osc). Just curious as planning to try osc on my rasa 

From what I have read the chip distance should be 29 mm with the window in, and still 29 mm with a filter but then the window should be removed. I assume there are two reasons for this. First, the effect of the filter on the light path (prolonging it with 1/3 of the filter glass thickness) is removed by taking out the window. Secondly, having both a widow and a filter may cause some refelction/halo problems, but the latter is just a guess. I actually have now idea why they put the optical window in there except that it gives Celestron a reason to sell their light pollution filter that can be bought to replace the window.