130PDS or 150PDS?

[matt_baker]

I'm planning on getting a HEQ5 Pro mount as a good starter so I can get properly into deep sky imaging. My current saving goals are to save for: A CC, guide scope, an astro-modified 450D and the scope + mount

My question however is do I go with a 150PDS or a 130PDS?

The 150PDS is heavier but also has more light gathering power at the same f ratio, but has a longer focal length too. I presume the HEQ5 can handle this mount with ease with wind not really affecting it.

Or the 130PDS which is cheaper, shorter focal length, lighter but has less light gathering power.

Does the 33% more light gathering power really affect DSO imaging without sacrificing time with the 130PDS?

I'd really love to know so I can make a decision. 

The image on my profile picture is an example of what I was able to achieve with alt-az imaging of M42 with 100 15 second only exposures so having an eq mount will make it so much easier for me

Thanks,

Matt 

[pipnina]

As an owner of a 130PDS I have wondered if the extra 2cm would make much of a difference... But given as I have seen some people's photos that look about as sharp as mine with 50mm less aperture I figure there isn't much to be gained there...

As far as the HEQ5 goes, I have had people tell me they can put 10" scopes on there (provided they use guiding and balance / polar align well).

In the end, I think 130 or 150 will be fine. If you wanted to go planet or tiny galaxy hunting maybe a bigger scope (like 200 or 250mm) would be noticably better.

[alexbb]

Hello, Matt!

There are plenty of examples of what you can image with an 130PDS. I've them both, though I didn't have time yet to image with the 150.

The 150 is bigger, looks almost like a scope, the 130 is almost like a toy. However, the mount is very important. If you get a good example of HEQ5, the 150PDS should be fine. If you get a bad example, then you won't even benefit of a smaller scope's resolution. What CC are you going to use? The SW reduces the FL by 0.9x (I measured the 130's reduced FL to 588mm). The Baader MPCC is of a better quality, but non reducing. By using the SW CC and a Canon 450D, you get 1.8"/pixel and 1.56"/pixel respectively. The mount should track about twice as good in order to benefit of the resolution.

If I were you, for starting, I'd choose the 130.

Also useful, try to get an idea about the FOV. Enter your camera/scope characteristics here and find out what you can see:
http://astronomy.tools/calculators/field_of_view/
https://dso-browser.com/ (click on a target)

HTH,

Alex

[spillage]

My 150 does weight allot more than my 130. I find that the 130 gives me great images am once on the mount I am more than happy to keep it there. What I like more about the 130 is that being so small it is not effected by the elements and I have manged to image when the wind would have caused me issue with a larger scope.

[wimvb]

I think @spillage makes a valid point in favour of the smaller scope. The 150pds has slightly more light gathering power, but the longer focal length, distributes that light differently over your pixels. In the end the difference is small. I would check fov of both scopes, and go with the one that suits your intended targets best.