Reduce Diffration Effects

[Shelster1973]

Hey all,

Beena while since I was last on here as weather has notr been that great in the glorious Plymouth area and have had not had chance to do other commitments.

However, last night I made the most of what was a relatively clear and calm night and set-up in the garden ready for some lunar imaging and also to see if I could get anything else.

Managed to get a good look at Jupiter and her moons and also managed to grab a few pics of her too.  These were taken while the sky was slight fairtly light, so had blue background, but what i did notice was the 4 very distinct spikes coming out from her.  At first I was wondering if this was soething wrong with my set-up, but after some looking on internet today, have found out that this is in fact the diffraction caused by the secondary spider.

Whilst I am not hugely worried about it as it is something that will always be present with the set-up I have (you canny change the laws of physics) was wondering if there is a way of resucing the effect down to a minimum.

Managed to get a few images of the moon and also grabbed some 1080p 24 video too.  Also, in my looking at the diffraction effect today, saw someone mention that the scope I have is not exactly the best for imaging the moon due to it's high speed.  Not sure how true that is but I am having some focusing issues.

Whilst I am using the Live View on my camera (Nikon D7100) I feel I may be better served by having this run off a laptop so that I can control it all from there.  Any thoughs on the bast way to achieve this? 

I amy put the images up later on tonight after I have converted them from RAW and accepted the fact I would open myself up to ridicule :-)

[Cornelius Varley]

What telescope do you have ?

[Shelster1973]

Doh, thought I had a signature with the details in....guess I will get onto that too.

Have an Orion 8" f3.9 Newtonian on a Celestron Advanced VX Mount

[ronin]

Afraid it is normal on a reflector, 4 vanes = 4 spikes, 3 vanes = 3 spikes.

There are curved vanes available and these do not so much reduce the effect they simply spread it over a wider ares so they are less promonent.

[Ptarmigan]

An aperture mask positioned in one of the quadrants formed by the vanes thus avoiding the vanes.

You may find this thread interesting reading as well http://stargazerslounge.com/topic/213403-curved-v-straight-secondary-support/?view=getnewpost

[Shelster1973]

An aperture mask positioned in one of the quadrants formed by the vanes thus avoiding the vanes.

You may find this thread interesting reading as well http://stargazerslounge.com/topic/213403-curved-v-straight-secondary-support/?view=getnewpost

Cheers for the info...kind of makes sense now I have looked at images of what you have mentioned as to whey there are a few capped holes in the dust cover for the scope...pre-made masks.

Will give them a go and see what effect they have

[Ptarmigan]

holes in the dust cover for the scope...pre-made masks.

Ah good, you have them then, I nearly mentioned them but not knowing your particular scope I thought it might muddy the waters

Good luck