Gina's All Sky Camera Mark 6 with Fujinon 1.4mm Fisheye Lens

[Gina]

Thank you

I'll see if I can find the info about the dome and yes, I'm quite happy to share my 3D printed parts designs.  The filament is ABS.

[Gina]

Sky still clear

[Horwig]

3 hours ago, Gina said:

There is something wrong with the RPi control of both dew heaters and cooling - neither are working.  Just something not connected I would think.  The camera is running at +12C with an ambient of about -2C

Hang on, are these images taken with an UNCOOLED camera, I'm speechless, they are so clean, my ASC using a QHY 5II are so much more noisy it's not true.

Oh no, do I have to go spending again...

 

H

[Gina]

The new lens is producing such a bright image that only 10s exposures are required

Here's another screenshot of KStars FITS Viewer with a touch of curves applied in GIMP.  Cropped to image area.

[Gina]

12 hours ago, Horwig said:

Hang on, are these images taken with an UNCOOLED camera, I'm speechless, they are so clean, my ASC using a QHY 5II are so much more noisy it's not true.

Oh no, do I have to go spending again...

 

H

I used a QHY 5II but I too found it very noisy!  I can unreservedly recommend the ZWO CMOS cameras - sensitive and low noise.  For DSO imaging with NB filters and mono camera, you do need cooling though.

[Gina]

C-CS adapter has arrived so I can try setting the focus "screw-wise".  Getting such good focus over most of the field was pure luck yesterday as I only slid the lens in and out of the adapter that is used to align it with the camera!  BUT it isn't in focus over the whole field and that's what's needed.  I assume the lens must be tilted in spite of the adapter.  Strange thing is that the field looks perfectly flat over more than half the image then seemingly suddenly bends away.  Weird!

What I omitted to try last night was to remove the dome and see what difference it made.  Maybe I should try that first before moving the lens.  Trouble is, I can only test this on a clear night with lots of clear stars - it just isn't possible to test the focus in daytime.  I tried it yesterday on distant trees and couldn't tell.  Again today the visibility is too poor to focus clearly at a large distance.

[Gina]

Here's a screenshot of KStars FITS Viewer with the ASC back on the guttering but without dome.  I've also rotated it so that north is at the top.  Certainly out of focus but whether the same amount all round I cant tell yet.  My observatory can be seen bottom left.

[Gina]

Another screenshot now with stars.

[Gina]

I've now put the dome back on and here's the result.  The focus is still out so must have changed since last night.  Something not tight I should think.  I'll take it back in and try the C-CS adapter as I've lost that fluke good focus anyway.

[Gina]

My all sky camera has captured a U.F.O.

[Gina]

Focused by unscrewing lens and clamping straight with adapter and clamp screw.  Here is a screenshot of the image with camera outside - no dome.  Focus seems pretty good except right at the top (north).  I could live with this   Now to try adding the dome...

[Gina]

 Dome added.  As before exposure of 10s uncooled with camera temperature of 14.5C and gain of 210.

[Gina]

A few small adjustments to improve the image.  Increased exposure to 15s, increased gain to 310 and drew the curtains to cut out the light in front of the house  

Tomorrow I think I'll secure the case sections and dome outer ring - maybe add some silicone grease to seal the edge of the dome to the outer ring to stop wet getting in - and put the whole thing including mast in it's proper place on the side of the observatory where it will be upright and cover the sky better.

[Gina]

Might try another odd tweak or two but this is pretty much there I think   I could take the Peltier TEC out as cooling is clearly not needed any more or at least it isn't in winter but I think I had better get the dew heaters working.  Probably leave the Peltier TEC for now - "if it ain't broke don't fix it"

[Gina]

[Gina]

ASC is now set up in its permanent position on the side of the observatory.  I fastened the dome outer ring to the main casing but otherwise haven't touched it - been busy with other things and I can bring it indoors again if I find I get any dewing up.  The dew heaters are not connected ATM.

Here's a screenshot from KStars with camera set to minimum exposure, gain and brightness.  The sun has yet to set.

[Gina]

Sun's gone down now.

[Gina]

Latest image.

[Gina]

Saved image.  No processing.

[Gina]

Screenshot of KStars FITS Viewer cropped to FOV and adjusted with curves in GIMP.

[ChrisLX200]

Good result Gina, you obviously have a darker sky than I do - Milky Way very obvious in your capture! I tend to use 8sec exposures with this Fujinon lens and that's good enough to show the quality of the seeing - I'm just processing last Fridays imaging run which was ruined by high Cirrus, the camera showed the potential problem well enough but I stupidly ignored it and went for RGB on M42. Captured data was useless sadly. I'll post the animation when it's uploaded to YouTube.

I tend not to use a Dome with this lens as it seems to be sensitive to reflections and distortions, so I just push the camera out the door of the Obs during an imaging run. There's a lot of glass pointing at the sky but it hasn't misted over yet - perhaps because the camera keeps it just warm enough to prevent it (or I've simply been lucky!).

ChrisH

[Gina]

Thanks Chris   Yes, pretty dark here - probably almost as good as it gets in this country

I wondered about not using the dome and sealing onto the edge of the lens to keep wet out of the works.  But I don't think I want to leave the objective glass open to the environment all the time and, in fact, the dome isn't too bad.  Yes, it does give reflections from bright lights and from the moon I expect. 

Another possibility is that I have some Baader optical film like that used with their solar filter material.  It's very thin and would probably have negligible affect on the imaging.  OTOH not sure how strong it is or how long it would last before needing replacing.

Yet another idea would be a shutter arranged to swing clear of the lens when imaging but to close up over the top and keep rain and bird droppings off when the camera wasn't in use.

However, I think I'll just stick with the dome for now as it seems quite adequate.  I might see if I can arrange some little screens around the edge to cut out the light from my house and other light sources around the edge.  Yes, I'm actually getting a larger FOV than I really want   It's a great lens and I'm most grateful to you for selling it to me

[ChrisLX200]

I also get some reflections around the edge but it's not too distracting. This vid is last Friday's RGB disaster, I'm hoping for better tonight - if not I'm giving up on RGB from here!

ChrisH

[mhard26339]

Hi Gina,

Excellent as usual, great job. A while ago I was collecting bits for an ASC but an Ocullus came up S/H at a price I could not ignore so I bought it, However, for followers of this thread I did much research into domes and ended up buying one from http://www.sunlightplastics.co.uk/acrylic-domes/?gclid=CM-2i9TypMQCFayWtAodoi4AOA The product was very good and not expensive, for those without a 3D printer I started to assemble mine in one of these https://www.tlc-direct.co.uk/Products/WK1010G.html cut away the top area, the dome (100mm  from memory) fitted well; may be of use to someone on here.

Regards

Mike

[Gina]

Good luck with you ASC Mike