Esprit 100 Pinched optics?

[Spongey]

Thanks to all for your responses. 

2 hours ago, Laurin Dave said:

have similar with my Espirt100, I contacted FLO and got this response:-

Dave, I got a similar response to you from FLO and have also decided to keep the scope as is. If it becomes a real issue over winter then I might reassess but I can live with it for now.

5 hours ago, Adam J said:

You need to upload a full resolution image I feel like that is a down sampled, but perhaps its just the big pixels on the 6D?

Adam, this is a full resolution image; unfortunately the big pixels on the 6D mean that I am undersampling significantly. I plan to resolve this with a new dedicated astro-camera in the coming months

5 hours ago, Adam J said:

You would do well to test by pointing at something like m45

That's a good idea, and the spacing between the bright stars will also show how the effect differs over the frame. I am running a sequence on M45 now to test.

Thanks again to everyone who responded, you have helped put my mind at ease

Cheers

[Adam J]

3 hours ago, Laurin Dave said:

We have seen this quite a bit on the Esprit and various Taks as well. There is no easy answer, we can have Es loosen them but then in warm temps you run the risk of one of the elements moving slightly and introducing coma into the image.

kinda, as I understand it the esprit also makes use of silicon plugs to help hold the lens cell, essentially they move the lens elements into position and then silicon them via these plus and then back off the adjustment screws a little.

Credit for this image to interferometry blog.

So unless you dig out the silicon its never going to be totally free to move.

That sort of stuff makes it a very good design in general, certainly better than some other more expensive chinese rebrands.

Adam

Edited November 3, 2020 by Adam J

[Spongey]

A quick 1 hour integration on M45, cropped to the main cluster as the edge stars aren't great with a 40mm image circle on my sensor anyway. This has only been DBE'd and lightly stretched, and is uploaded in full resolution. As you can see the effect is visible on all of the bright stars, and also some of the smaller ones. Last night was much colder, around 2 degrees for this hour and again I had the dew heater running on full whack. Any further thoughts?

P.S. I know I need to take new flats 😉

 

I also did a short run on M31 last night. The effect is also visible on a lot of the stars in this image, down to magnitude 10 (cropped but uploaded at full resolution):

Edited November 4, 2020 by Spongey

[Adam J]

This is my m45 test with my esprit 100 and a ASI1600mm pro, so of course you have issues with micro lens diffraction with the camera. That makes it harder to see the effect you have if it is present at all. Ill let you judge.

Adam

[Laurin Dave]

That looks very similar to mine Spongey and you've got Merope's Nebula so can't be that bad.   Here's my M45 with 6 micron pixels..  diffraction spikes courtesy of the KAF sensor ..     I did try running with the dew band on full whack but it messed up my autofocus... so backed it off again.

Dave

 

[AndyThilo]

They all look great, much better then my old mess here - 

[Adam J]

5 hours ago, AndyThilo said:

They all look great, much better then my old mess here - 

yes that is horrible 100% unacceptable, what was the outcome for you?

Adam

[AndyThilo]

That was the first of 3 scopes. Al had similar problems, in the end I got a refund and bought an ES102 Carbon. But now have an WO GT81 which is incredible. 

[Adam J]

On 04/11/2020 at 18:33, AndyThilo said:

That was the first of 3 scopes. Al had similar problems, in the end I got a refund and bought an ES102 Carbon. But now have an WO GT81 which is incredible. 

Well to be honest I have seen some very very bad GT81s too so it really is the luck of the draw. Triplet refractors are a mine field hence why I chose my retailer with care.

Adam

[AndyThilo]

Yeah very true, bought the GT81 from FLO, already checked and tuned and it is superb and thankfully space grey, not a gaudy red/gold or blue