M106, galaxies and refractors...

[ollypenrice]

I'm still undecided about how to proceed with a higher resolution imaging system. My longest in-house focal length at the moment is a metre with the TEC140. It's a lovely sharp optical system with a perfect focuser.

At the moment I'm imaging at 1.8 arcsecs per pixel with the Atik 11000. I could put that camera in a long FL scope or I could put a Sony small pixel camera in the TEC. Hmmm...  I reprocessed some old Tec data at I.56"P/P from an Atik 4000 to see how good I could get it since I last imaged galaxies in this scope some years ago. It came out like this. (I hope this will take you to a full res when clicked upon!)

 

 

If I went for an Atik One Nine I could have 0.78"P/P so the galaxy would be nearly twice as big on the screen at full size and would, of course, be more highly resolved. (When imaging with the ODK14 we were at 0.66"PP so the difference is not all that great.) Alas Atik don't do the 4120 in monochrome but that would take me to the same pixel scale as we had with the big scope - 0.65"P/P. I certainly don't want OSC though*, and changing to another brand of camera would be a wrench and something I don't really want to do becasue I'm a happy customer. So the same as above but with nearly twice the resolution in terms of pixel scale.

What do you reckon? Since I have a 1.25 filterset this would be a lot cheaper than buying a bigger scope. Chip size is not important because, for big targets, we have big chips avaiable already.

Olly

* I'd want to do planetaries with it so Ha and OIII would be key players, hence mono.

 

[pipnina]

Maybe use a barlow lens in one of your existing fracs? Then you'll have roughly your target px/arcsec. Or is the point to have the same or similar FOV with more pixels? If it's the latter, drizzle sounds like the most economic solution. (It's good enough for NASA ) We got our best images of the far universe and the outer solar system using that... And if I'm not mistaken it's available in PixInsight, you'd just need to set your mount up for some interpolation.(A feature normally used for DSLRs i think?) (I'd guess at 3/4 arcseconds movement being enough).

My £0.02.

    ~pip

[ChrisLX200]

Trouble with the large 'fracs is they offer a big image circle, 60mm and up - which should be a good thing, but only if you have a sensor that makes use of it. Otherwise you're not recording a good proportion of the light it's catching. A large RC/DK or whatever with a smaller image circle at least puts more of its light onto the chip...

ChrisH

[Starlight 1]

I started on this one with the tak 106 & 864 ccd and that run at 1.76 pp and look much the same as your in size , so looking forward to more posts on what you are trying to do.

PS Nice image Olly.

[nmoushon]

My first thought would be to go smaller pix camera but as pipnina said a barlow could possibly do a similar job. If your intent is to use it for small targets like galaxies and PNs I think it could work. Just as long as the barlow plays nice with the rest of the optics. 

If you dont want to go that route then I would at least give moving the camera a try. It might disrupt your set up for a while but at least you wont be out any money. I think from there you would have a better judgement as to what you would need to do (new camera or new scope). 

[ChrisLX200]

By way of coincidence, I was trying out my ODK12 tonight, under poor conditions... and with a stupid Crayford focuser that wouldn't (focus). I never liked Crayfords and after tonight I truely detest them! Anyway, I couldn't auto-focus so had to guess best focus from the on-screen star image, plus the focuser wobbled like a jelly so my 10M mount could not produce a decent model (consequently the tracking was poor too). I could go on, but bearing all those caveats in mind this is a stack of 8 x 5min lum subs of M106. I don't think the result comes even close to establishing what resolution the Atik490EX is capable of producing in combination with a 2040mm f/l OTA but perhaps it shows promise. Certainly more detail can be seen in this than I managed to achieve with the same camera + Televue NP127is under better conditions (and focus...).

ChrisH

[Rodd]

On 2/14/2016 at 12:51, ollypenrice said:

I'm still undecided about how to proceed with a higher resolution imaging system. My longest in-house focal length at the moment is a metre with the TEC140. It's a lovely sharp optical system with a perfect focuser.

At the moment I'm imaging at 1.8 arcsecs per pixel with the Atik 11000. I could put that camera in a long FL scope or I could put a Sony small pixel camera in the TEC. Hmmm...  I reprocessed some old Tec data at I.56"P/P from an Atik 4000 to see how good I could get it since I last imaged galaxies in this scope some years ago. It came out like this. (I hope this will take you to a full res when clicked upon!)

 

 

If I went for an Atik One Nine I could have 0.78"P/P so the galaxy would be nearly twice as big on the screen at full size and would, of course, be more highly resolved. (When imaging with the ODK14 we were at 0.66"PP so the difference is not all that great.) Alas Atik don't do the 4120 in monochrome but that would take me to the same pixel scale as we had with the big scope - 0.65"P/P. I certainly don't want OSC though*, and changing to another brand of camera would be a wrench and something I don't really want to do becasue I'm a happy customer. So the same as above but with nearly twice the resolution in terms of pixel scale.

What do you reckon? Since I have a 1.25 filterset this would be a lot cheaper than buying a bigger scope. Chip size is not important because, for big targets, we have big chips avaiable already.

Olly

* I'd want to do planetaries with it so Ha and OIII would be key players, hence mono.

 

Depends on seeing--you probably get good seeing at the observatory--but is it really .5?  even .8?

[ollypenrice]

13 hours ago, ChrisLX200 said:

By way of coincidence, I was trying out my ODK12 tonight, under poor conditions... and with a stupid Crayford focuser that wouldn't (focus). I never liked Crayfords and after tonight I truely detest them! Anyway, I couldn't auto-focus so had to guess best focus from the on-screen star image, plus the focuser wobbled like a jelly so my 10M mount could not produce a decent model (consequently the tracking was poor too). I could go on, but bearing all those caveats in mind this is a stack of 8 x 5min lum subs of M106. I don't think the result comes even close to establishing what resolution the Atik490EX is capable of producing in combination with a 2040mm f/l OTA but perhaps it shows promise. Certainly more detail can be seen in this than I managed to achieve with the same camera + Televue NP127is under better conditions (and focus...).

ChrisH

I'm happy to welcome you to the Worshipful Order of C-word Despisers, Chris. I can't bring myself to type the word itself. Why they put a tenth rate focuser on an excellent set of optics is a mystery, but they do. Still, that's very highly resolved and shows that you (and we) will be in for a festival of fine galaxies. Lovely detail right into the core.

1 hour ago, Rodd said:

Depends on seeing--you probably get good seeing at the observatory--but is it really .5?  even .8?

Hard to say. I think it might be. We've imaged at 0.66 and done nicely but whether going to an arcsec would have made any difference is anybody's guess.

Olly

[ChrisLX200]

Just now, ollypenrice said:

I'm happy to welcome you to the Worshipful Order of C-word Despisers, Chris. I can't bring myself to type the word itself. Why they put a tenth rate focuser on an excellent set of optics is a mystery, but they do. Still, that's very highly resolved and shows that you (and we) will be in for a festival of fine galaxies. Lovely detail right into the core.

Olly

That focuser cost me a good tea mug which I discovered doesn't bounce when thrown against a wall...  ;-)

ChrisH

[ollypenrice]

10 minutes ago, ChrisLX200 said:

That focuser cost me a good tea mug which I discovered doesn't bounce when thrown against a wall...  ;-)

ChrisH

Better that than a TeleVue Ethos...

[gorann]

Now when I got an EQ8 on the pier I thought of trying something biggish for galaxy hunting. I am going to visit a friend in Alaska in May and I am thinking about ordering an Edge 11 to his address to bring home (in a big padded suitcase - that is the scary part). It is half price compared to here (i.e. around 3000 USD rather than 5200 Euro). I have been thinking about 12 " RCs but at this price range I am not sure about their quality, and I like something more dust proof. I have an Edge 8 and never even had to collimate it. What do you think?