Andromeda Galaxy - captured before the haze comes back!

timatworksg · Post by **timatworksg** » Tue Nov 02, 2010 1:01 pm

@Orly: Not sure about that....time to skim the web...but good question.

@CloudCover: Arm and leg? I need to rob more than one bank..haha! Still dreaming of the day though! Perhaps...sigh**

Post by **weixing** » Tue Nov 02, 2010 1:10 pm

Hi,
Nice shot!!

Very on leh... I "sian" already when I look at the weather...

Have a nice day.

orly_andico · Post by **orly_andico** » Tue Nov 02, 2010 1:20 pm

Astro-Tech 65EDQ -- quadruplet lens for not an arm and a leg.

cloud_cover · Post by **cloud_cover** » Tue Nov 02, 2010 1:30 pm

Orly --> Yeah but $549 for a 65mm is expensive, size for size

Still, I think its prob cheaper to buy an external flattener, not to mention probably lighter although the imaging ttrain is probably longer.
I wonder if flatness can be edited in photoshop...

wucheeyiun · Post by **wucheeyiun** » Tue Nov 02, 2010 1:35 pm

Vixen NA140 is a decent prices quad lens Achromat
http://www.astromart.com/articles/artic ... cle_id=119

orly_andico · Post by **orly_andico** » Tue Nov 02, 2010 2:15 pm

One other possibility... the Nikon 180mm f/2.8 ED :-)

You can get it for $350 on KEH (even the old manual-focus one will do, so long as it's the ED version) and it has way more than four elements!

The Vixen 140 Neo-Achromat is a largish tube, so there would be challenges there in mounting..

orly_andico · Post by **orly_andico** » Tue Nov 02, 2010 2:16 pm

cloud_cover wrote:Orly --> Yeah but $549 for a 65mm is expensive, size for size
Still, I think its prob cheaper to buy an external flattener, not to mention probably lighter although the imaging ttrain is probably longer.
I wonder if flatness can be edited in photoshop...

Tell that to the guys who buy Tak FS60C or Televue 60IS. Both are doublets and cost way more than $549!

There's a new Tak FS60Q I believe which is a quad.

cloud_cover · Post by **cloud_cover** » Tue Nov 02, 2010 2:37 pm

Apples to apples, bro! Cannot compare a tak to an AT scope! Next thing you'll be comparing an EQ6 to an AP Mach1 ;)
The Vixen NA140 is afterall, an achromat so as far as IMAGING is concerned its less useful. Still can be done, violet rim can still be digitally processed but of course not as good as a proper apochromat itself. Don't forget there's a very great difference between the amount of fringe the eyes see vs a camera sees.
Having said that, I think its not the number of lens elements that's important, but rather what each element does. So while the 180mm is great for wide field (You can't really find a telescope with 180mm) but having all those extra elements may not be advantageous compared to a 4 element setup, since each lens will absorb some light.

mch3898 · Post by **mch3898** » Tue Nov 02, 2010 9:05 pm

orly_andico wrote:as an aside... is a flattener even needed for the DSI? the DSI has such a teeny tiny chip...

and how to attach flattener to DSI? mine (WO Flat-2) has an SCT thread or 2" barrel on one end, and a T-thread on the other end. But my DSI nosepiece is a 1.25" barrel..

Hi Orly,

By the way, the chip size of my DSI Pro III is 10.2mm x8.3mm and my StarShoot Pro V2 is 25.1mm x 17.6mm. Will a flattener be beneficial?

As for mounting the DSI to the flattener, I guess a filter wheel helps. I used the Orion Filter Wheel and the set up is as shown.

[img][img]http://farm5.static.flickr.com/4034/513 ... e65a89.jpg[/img] IMG_8025 by mch3898, on Flickr[/img]

cloud_cover · Post by **cloud_cover** » Wed Nov 03, 2010 12:17 am

I don't know about the mounting but some field curvature was visible in your cropped photo through your starshoot pro so I guess it should help. Go borrow one to try. You don't even need to take (relatively) long exposures (obviating the need for meticulous setup) since you're not interested in the DSOs but rather the bright stars, particularly at the edge of your field.
I rather suspect the DSI will have less issues, but the penalty is the smaller chip.