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acharris77

Need Some Advice On Internal Reflections on 130P DS

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Hi all I need some advice. I think I might have an issue with my 130p DS and internal light pollution reflection.

I have noticed the year that no matter what I image or which part of the sky, I am getting terrible LP and gradients in my images. I know I have gotten LP as I am not away from street lights, but I could image in Ursa Major and most objects above my head with only a little LP as they are away from the street lights.

Now if I shoot in the same part of the skies then I get terrible gradients, which I will show below. I was advised that it could be internal reflection and if so other than flocking it, is there anything else simple that can be suggested. The scope only cost me  £110 new on Astro boot 2 years ago, so probably paying someone to do it is not very cost effective. 

The gradient is not even and it is a funny shape. It looks worse if I shoot lower in the sky and all my M42 images suffered from the same pattern and it makes the subs useless and need to be binned. As much as I love my 130P DS and it did deliver great images untill the last 9 months to a year and now imaging is less rewarding. I don't know what to do. Any help is appreciated.

Thanks.

For Forum.jpg

Edited by acharris77

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Hi, you could try flocking the inside of the OTA, it's not to much of a task on a 130P. I used some fine black felt which i bought for £3.50 from Boyes which i then stuck on with PVA glue. It has certainly got rid of a cast i had in mine

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Hello, flocking would be worth a try. And see if there is an improvement 

But as you admit you have some street lights that are causing light pollution. The 130p DS is a very transportable scope. I would get in the car and get to a dark site and try some imagine from there. Probably well worth the trip .  

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Thanks all. I was looking at flocking on google. I haven't got the confidence to strip it down and put it back together as I know something will go wrong or I can't get the collimation right.

I was looking at some people say that just flocking the area opposite the focuser will help cut down unwanted light. I will have to think about what I am going to do with it.

Thanks again.

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I would flock as much as the scope as you feel comfortable doing.
I also took the extra step of flocking the inside and outside of the focuser tube.
Use a black sharpie and black out as many of the screws etc...

You can remove the front white ring around the tube and this will give you a little more room between the spiders just be careful not to bend them.
 

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Just in case - cover the rear of the view finder that you look through. It is not uncommon that light gets in through this and causes problems. The presumption is that all the light is getting in only from the "front" but some of the sneaky stuff creeps in from the rear. And as you say you have a fair amount of LP that is a possibility that needs eliminating.

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