2 replies to this topic

[John Berger]

Galaxy season is approaching, or kind of here already

 

so I really want to increase my focal length

 

I got confused on how to do this for a sec, because I didn't want to sell my 65PHQ, and I wanted to put it to use somehow, if I were to move to a longer FL

 

so after a few days of thinking, I woke up one morning with (what I think is) the coolest idea

 

my idea is to buy an Askar 120 APO, with the 1x flattener, put my 2600mm, EFW, OAG on that (and maybe would have to buy another ASIair), then piggyback my 65phq on the 120 APO, and attach my 533mc pro (which I'm currently not using for anything), on the 65phq

 

here is an image showing what I mean in terms of FOVs

the square is the color sensor, the rectangle frame is the mono

 

the color is at 2x larger pixel scale than the mono

 

all I need to do to use my color setup is just crop out the bottom and top areas in the subs taken with the 533 (will automatically happen if my 120 APO is used as a reference for stacking)

 

so I would only have to buy the 120 APO, and I can use my 65PHQ for getting color at basically Bin 2 (compared to the 120 APO setup, in terms of resolution), and I remember pros saying that your color could be at Bin 2, while your mono is at Bin 1

 

so I could maybe finally complete full projects in one night, doing L at 0.92"/px while OSC is being taken at 1.86"/px, so I could then do LRGB

 

my question is, is this a good idea? seems like a good use for my 65PHQ if I buy a long FL refractor

Edited by John Berger, 16 February 2025 - 05:00 AM.

[DeepSky Di]

It may seem a bit counterintuitive, but try the 533 on the Askar 120 in Stellarium on the galaxies you are interested in. 

 

If the AVX is the only mount, add up all the weight for both optical trains and make sure it's going to work (short version: skeptical). On the other hand, consider a second mount and then get into running two rigs at a time. As a minimum, the 65PHQ could go on a  SW GTi and be a travel rig.

[unimatrix0]

It really comes down on what galaxies you are planning to image.  If you want to go for like the Whirlpool and the Cigar and similar, then you could just use your 533mcpro camera, you really don't need an APS-C size for them. 

 

If you want like the entire Markarian's Chain , then a wide field scope like the 65mm with an APS-C would frame all those tiny galaxies nicely.  Smaller galaxies require even less of a camera, like the 585 or some people even go even smaller sensors like one of those planetary cameras, especially still having the colder weather sticking around cooling is not needed as much. 

Edited by unimatrix0, 16 February 2025 - 10:59 AM.