iwols

just wondered if anyone had added one of these to there c8 edge ?  and how they found them thanks

this is an image i took a while back similar to yours but not as clear lum@5 mins

On 12/11/2021 at 15:48, vlaiv said:

Well, sure that you can get cheaper, I just did not how you feel about CMOS sensors and software binning.

I have ASI1600 and like it a lot, but if I was in the market for similar camera today - I'd probably go for ASI294mm instead. It has better QE and it is a bit larger (23.1 mm vs 21.9mm diagonal). Both will work well with 1.25" filters.

ASI294 can be "unlocked" to 2.3µm pixel size.

If you bin that x3 - you'll get 6.9µm pixel size which is very close to what you have now. That will result in 2760 x 1880 px camera.

For use with EdgeHD - you can bin x6 for example - that will give you effective 13.8µm pixel size or 1.43"/px and you will still have 1380 x 940 px - which is similar to pixel count you have now.

I use my ASI1600 on 80 F/6 apo and RC8" scope. With former I use it natively (with reducer / flattener) for 2"/px while with later - I bin either x2 or x3 for 1"/px or 1.5"/px - depending on what I'm imaging.

This is for example 80mm at 2"/px - at 100% zoom (M13):

This is RC8" at 1"/px at 100% zoom (although image is more like 1.5"-2"/px):

 

 

hi vlaiv what do you think about adding a 0.7 x reducer to my edge to give me that extra fl over my tsoptics@600mm and possibly improve my image with the edge,what would it mean to my sampling rate please

hi all presume from the views /replies no one has gone this way?😁

Just wondered if anyone had gone this way and what their thoughts were thanks

Hi Olly ,i used it for planetary and now use it for deep sky just to get a little closer than my 100mm ts 

tha

3 hours ago, vlaiv said:

Ok, see - that is the thing,

If you add telecentric lens to your TS scope - you won't have "more zoom" - without stars also being larger.

Size of stars in the image has to do with sampling rate and how well it is matched to detail present in the image. Detail in the image will depend on several factors combined - size and quality of aperture, seeing and mount performance.

Once you reach the limit set by detail in the image (and that is measured by star FWHM) any additional "zoom" will simply make your stars look large / bloated.

That limit for most of us, on most days of the year is around 2"/px for scopes up to 4", 1.5-1.6"/px for 6" scopes and 1.4"/px for 8" scopes. On very good night, you can go down to 1-1.2" with 8" scope - but that is rare.

With 100mm F/5.8 and 6.45µm size you have ~2.3"/px - that is very good match - right there close to limit of what looks good. It is no wonder you are happy with star size and that combination.

With 2000mm FL and 6.45µm pixel size, you have 0.67"/px - that is at least twice as much then is realistically needed - it is like zooming in your image x2 - or x2.5 past what looks good. No wonder you feel that stars are large.

2" version - https://www.firstlightoptics.com/barlows/explore-scientific-2x-barlow-focal-extender-2.html

1.25" version - https://www.firstlightoptics.com/barlows/explore-scientific-2x-3x-5x-barlow-focal-extender-125.html

However - I would not try either of those unless someone can confirm that it will work with quadruplet scope. I can't be certain that it will work properly with such scope. It will work fine with regular scope without flattener, but I simply don't know if it will work with your scope at all.

There are some alternatives for you to consider - that might be better choices to get what you want.

1. Replacing your camera?

One of problems that you have is that it is not feasible to bin x2 your camera as it has low pixel count. Binning will produce ~700 x 500 px image - and that is tiny by today's standards.

If you get camera with larger sensor  - maybe it will work better for you?

Say you have camera like atik 16200 with 6µm pixel size and 4500 x 3600 px. You can use such camera in bin x1 mode on TS 100mm for about same resolution you now have - 2.13"/px, and you can bin that camera x2 when you use it on EdgeHD - to make it work at 1.24"/px or even x3 to get 1.86"/px.

Even if you bin x3 - you'll still end up with 1500x1200px image size - that is larger than you have now.

2. Add scope that is about 5-6" and ~900mm of focal length.

It can be refractor - something like this:

https://www.teleskop-express.de/shop/product_info.php/info/p6679_TS-Optics-PHOTOLINE-130-mm-f-7-FPL53-Triplet-APO-Refractor.html

or maybe even 6" F/6 reflector? (not sure if you'll like that, collimation and all)

 

 

thanks vlaiv is there anything cheaper than  the 16200 you could suggest ,looking at the barlows i would not have enough back focus,any thoughts on asi 1600? cheers

poor looking stars really or it may be that im not used to the star size being bigger than my ts optics,collimated back focus ok theres just something,can you suggest a specific lens? to look at

omg vlaiv your right,,would a 2x/2.5 barlow on my 600mm with an atik 414ex ccd work?  would i still be able to use my filter wheel /rotator back focus dependant and where would the barlow go on my imaging train

well i have the ts optics refractor q100 at fl600mm and a c8 edge at fl2032 and really struggle with the edge so just wondered if there is a refractor near to the edges focal length that anyone could suggest,thanks

just looking at these and how do they compare to say a c8 edge for image quality and ease of use thanks(just looking)

I too had the exact problem you described with the star tech so changed it for another cheaper make which works perfect came from amazon, it was that good I bought a spare will see what make it is when I get in if you still have problems 

does anyone know if the cable that comes with the pluto trigger is the same as   AP-R3N (N3) it looks the same,but pluto  call it a dc2 cable thanks

just not sure if it will fit my tripod as it has a cast pin (older type)

perfect thanks  john

just wondered if the above can be  used together or is there an adapter as my camera tripod is no where near as sturdy as the heq5 tripod would be thanks

2 hours ago, 900SL said:

No. You have to get the right exposure for a start, and ISO100 @1m is not the same as ISO1200 @20s.

ISO stops are 100,200,400,800,1600,3200 etc

For each ISO stop you halve the exposure, so for example

1min at 400

30s at 800

15s at 1600

 

You won't see anything at ISO 100 for 1min

 

What camera and lens are you using? A tracker can significantly improve MW shots with a good camera and lens

 

 

 

It's a nikon d750 with either a samyang 14mmf2..8 or tamron 24 - 135 mm

hyperthetically,would a 1min @ iso 100 be a lot better than a 20sec exposure at say iso 1200 thanks

a bit more processing

thanks andrew👍

thanks dave  went in car park and went left ,so the gate is on the opposite side of the road,what duration/quantity were your images and it really was a clear night first time ive been here,do you think the skywatcher adventurer would be any benefit?

Hi just took a few 25 second  images of the milky way on tripod and stacked in sequator,with iso up ect the image turned out ok,so i was just wondering what there would be to gain from using a star tracker,i know i can get longer images but whats the benefit as my 25 second images were quite bright any way,just looking for your thoughts thanks

Hope this link is working?

https://www.dropbox.com/sh/t1vov7hrgqu9khw/AAAmgfQy_Yic356vEgUgDQQia?dl=0      thanks

thanks olly all my files for this are here if anyone wants to have a go,would love to see how bad i am😁

link below