Testing fast scope on open clusters - NGC 633 and nearby clusters

[GalaxyGael]

Not too many clear skies at all these days, so on two short periods of OK seeing (mild high cloud haze), I imaged NGC 633 and nearby clusters (NGC 654, NGC 659 and IC166...).

2.5 hrs comprising 60 exposures of 150s

TS Hypergraph 6 at f/2.8, ASI 2600 MC Pro at -10C and Gain 100.

Master flats and darks, all on iOptron GEM45.

This was another test to fine tune the imaging train and mirrors, still some tweaking on the focuser and primary.

This scope look quite nice for star fields, getting deep enough to see the various bands of lower density stars with distance projected onto a flat image.  

This cluster has come interesting Be stars, slightly different off-white color, with stars of almost every color in the frame, some bright dust and clouds. Gorgeous region of sky I think.

[Dummy]

Wow absolutely amazing. Maybe I don't know what I'm talking about but this doesn't seem to me all that different from some HST picture of a globular. I zoomed all the way in and you couldn't all the stars in there even if you sat down looking at it for a year. 😮

[GalaxyGael]

19 hours ago, Dummy said:

Wow absolutely amazing. Maybe I don't know what I'm talking about but this doesn't seem to me all that different from some HST picture of a globular. I zoomed all the way in and you couldn't all the stars in there even if you sat down looking at it for a year. 😮

Thank you, and its a lovely region to image. It did turn out to have the 'fast reflector scope dazzle' between diffraction in a wide field of stars, and high luminosity at this focal ratio. I'm curious to fish around for similar regions and there are plenty of them.  

[Allinthehead]

This is lovely, can't beat a fast scope. I've often looked at imaging this region with my Epsilon, hopefully get around to it this year. I've only managed 6 hours of imaging in two months however.

[GalaxyGael]

It's a peachy bit of sky isn't it, and luckily had two partial nights given the weather we've had recently. It rained on the scope last time... 

[MalcolmM]

Fabulous photo and particularly interesting for me as I have been trying to find all these clusters visually in a 4" refractor from the suburbs. My notes say of NGC654, "Need averted vision, something there, you're just not sure what!"

I might print your photo (if that's allowed) and use it for a reference.

[GalaxyGael]

16 minutes ago, MalcolmM said:

I might print your photo (if that's allowed) and use it for a reference.

Good luck with the viewing. I had my 71 mm refractor out the other night for gaps in the clouds and it was fun.

Of course you can copy, save, print, share as you want. 

Its CC BY 4.0. Maybe I should add that to my signature

[tooth_dr]

Such a beautiful area! 
 

I noticed you have posted in the chip tilt thread. Have you tested your equipment?  The stars upper right above are a little mis shaped

[GalaxyGael]

38 minutes ago, tooth_dr said:

Such a beautiful area! 
 

I noticed you have posted in the chip tilt thread. Have you tested your equipment?  The stars upper right above are a little mis shaped

Thanks, It is a nice region. Sensor is now almost perfect, but focuser probably is not since I doubt it holds collimation when rotated, which I did. I suspect I 'perfectly' made the pair imperfect since they likely nearly cancelled each other out before I rotated the focuser to an easier position to manage. But it is not moving from where it is now, so its a few tweaks every now and then to sort it. Slight mis-shapen stars don't bother me too much to be honest, but working to eliminate them over time or at least not sacrifice imaging something I like while there is a funny corner such is the weather. Well, the images can only get a little better I suppose, something to look forward to . I also see some triangular ones on the bottom right, so playing with the tightness of one of the felt pads around the primary retaining ring to eliminate any possible pinching artefacts. But I know if tonight stays clear like it is right now, I can see my tweaking playing second fiddle for a while! 

I had a large flashlight taped to the estate entrance pillar, with multiple pinholes to give a 20 or so artificial stars about 50 m away. With the sensor system, I thought I was set since the collimation was freshly done, focuser rotated and sensor de-tilted. It was lynched by jays and rooks, crows etc. and I had no more gaffers tape. Not joking.

 

[Mr Spock]

That is a fabulous image. I love the natural colours.

[GalaxyGael]

54 minutes ago, Mr Spock said:

That is a fabulous image. I love the natural colours.

Thanks Michael

[tooth_dr]

1 hour ago, GalaxyGael said:

Thanks, It is a nice region. Sensor is now almost perfect, but focuser probably is not since I doubt it holds collimation when rotated, which I did. I suspect I 'perfectly' made the pair imperfect since they likely nearly cancelled each other out before I rotated the focuser to an easier position to manage. But it is not moving from where it is now, so its a few tweaks every now and then to sort it. Slight mis-shapen stars don't bother me too much to be honest, but working to eliminate them over time or at least not sacrifice imaging something I like while there is a funny corner such is the weather. Well, the images can only get a little better I suppose, something to look forward to . I also see some triangular ones on the bottom right, so playing with the tightness of one of the felt pads around the primary retaining ring to eliminate any possible pinching artefacts. But I know if tonight stays clear like it is right now, I can see my tweaking playing second fiddle for a while! 

I had a large flashlight taped to the estate entrance pillar, with multiple pinholes to give a 20 or so artificial stars about 50 m away. With the sensor system, I thought I was set since the collimation was freshly done, focuser rotated and sensor de-tilted. It was lynched by jays and rooks, crows etc. and I had no more gaffers tape. Not joking.

 

Yes indeed imaging takes priority.  My focuser rotates also, but I havent dared to touch it.  It's supposed to be collimated but I'm taking no chances  

[ollypenrice]

Very nice indeed with those dusty shapes setting of the rich starfield.

I'm learning my way with a fast scope as well and thinking about how to control the bright end - ie the stars.

Olly

[GalaxyGael]

4 hours ago, ollypenrice said:

Very nice indeed with those dusty shapes setting of the rich starfield.

I'm learning my way with a fast scope as well and thinking about how to control the bright end - ie the stars.

Olly

Thanks Olly,

Well its a region of sky that seems to have a lot to look at, and the bright and dark dust is just enough in the background to make it a bit more interesting to me. 

I used gain 100 on the ASI2600 MC with 150s exposures, although I am thinking about using gain 0  just to maximize the 50k well depth and keep the full DN. I chose not to shorten the exposure, and will probably stick to 150s or maybe 120s so that my PC can handle 4-5 hours of data if I go that far with this scope. Having said that, gain 100 pull sin a bit more and I dont feel like things have become saturated to teh point where colors are not correct for different stars. They seem to be I think.

[GalaxyGael]

I forgot to add that my SQM (not counting the LED street lights was about 20.01 at best using those settings

[peter shah]

5 hours ago, ollypenrice said:

I'm learning my way with a fast scope as well and thinking about how to control the bright end - ie the stars.

One of my tricks for that is to use a gaussian curve with a flat line at mid range to high. It helps retain star colour and keeps their brightness under control.  The main disadvantage is it keeps contrast very low so there is a need to use other methods of contrast enhancement to compensate.

[Craig a]

6 hours ago, peter shah said:

One of my tricks for that is to use a gaussian curve with a flat line at mid range to high. It helps retain star colour and keeps their brightness under control.  The main disadvantage is it keeps contrast very low so there is a need to use other methods of contrast enhancement to compensate.

What is a Gaussian curve Peter if you don’t mind me asking? 

[FaB-Bo-Peep]

Simply stunning!

[peter shah]

On 02/10/2021 at 20:34, Craig a said:

What is a Gaussian curve Peter if you don’t mind me asking? 

Its just an equally proportioned curve, so what I have described is technically not as the mid to upper ranges are adjusted.