AstroBinAstroBin
Contains:  Other
Trying my 86mm Apo with a 3x Barlow - fail, Arny

Trying my 86mm Apo with a 3x Barlow - fail

Trying my 86mm Apo with a 3x Barlow - fail, Arny

Trying my 86mm Apo with a 3x Barlow - fail

Description

Delibately ignoring physics I wanted to squeeze the most ot of my 86mm apo with 560mm focal length by using a 3x Barlow. 

Nice idea to have 1680mm focal length at hand, so I went for Pinwheel Galaxy for a couple of hours. 

Predictably -in hindsight- the result were sobering poor flat images of no value, not improvable by any magic tool. 

Results & learnings
- I had a to add almost 10cm extension tubes to get knto some kind of focus, increasing the length of the optical train significantly
- that total length drove flexure up
- coma effects were bad in the image
- the Barlow turned my scope from f/6,5 into f/19,5, which is a problem in many ways taking images
- imaging at my regular 5 min exposure had as mich   contrast as a black cat in a dark night
- increasing exposure to 10 minutes/frame and gain to 300 gave a bit better data, but adding much noise, which stacking couldn‘t improve the image much, as I could only take too few frames 
​​​​​​- learning: there are no shortcuts - just get a bigger scope if you need one :-) 

BUT: it was a beautiful full moon night otherwise yielding a nice gear shot :-)

Comments

In these collections

x_Gear
×

Warning!

This operation will reload the current page. If you have any unsaved information in a form, it will be lost.

You can also dismiss this window, and your operation will be applied at the next page navigation.