Thoughts from Starlight Cascade

Serenity Imaging Day 4
Still commissioning. Another hour last night from when the stars came out until the fog and dew stopped the work.
The 90 degree diagonal came off the scope. Why?
It is good to have when using an eyepiece (less bending over wayyyy to low) but for imaging it is better off off.
1) It extends the optical path and longer is not necessarily better.
2) You gain photons by eliminating the loss caused by the optical mirror surface, in general maybe a 10% gain.
3) You eliminate another optical flip in the image (from bouncing off a mirror)
4) This one is huge and I never thought of it until the diagonal came off… eliminating another source of dust and dirt in the image from the dust and dirt on the mirror. Holy cow Batman! It was dirty!

Schmidt Cassegrain reflector will produce an image that is upside down (flipY in firecapture parlance) when used without a diagonal. When a diagonal is used the image will be corrected right side up, but backwards from left to right (flipX in firecapture parlance)
Will confirm this with the moon next session.

Walking out to the Observatory was bad last night with high temperatures and high humidity… ground fog to a large degree and lots of dew.
Turned on the scope from the park position, went to Mars, then back and forth trying to achieve a new coarse focus of the primary mirror and actually having mars in the field of view of the camera. Removing the diagonal changed the coarse focus. After a few minutes, Mars was in the FOV and was coarsely focussed.
Fine microfocusing was next then some sample images, 30 seconds without firecapture alignment, 30 seconds with firecapture alignment and 60 seconds with alignment.

Goto Saturn next, still near its transit point almost due south. It was not quite in the FOV but was within the 1/2 degree telrad inner circle. A little bit of searching found it and four more images were taken: 30, 30, 60, and 90 seconds. By this time the telrad was dewed over, the primary mirror (still without a heater or shield) was dewing and it was time to go in.

So tonights session was: no diagonal, zwo asi120mc camera, no barlow, no focal reducer, no dew shield, no dew heater.
Oh! Here are the three mars images and the three saturn images:

Mars was the best 10% of the frames taken used to stack as seeing was poor, transparency was poor and Mars was still low in the Southeast. The south Polar Cap is showing as well as some dark features in the southern hemisphere.

30 sec no align

30 sec with align

60 sec with align

Saturn was the best 50% and only the 90 second image run is shown here. The Cassini division is finally showing!

Some years ago we realized that the increasing height of the sugar maple tree and two ash trees near the SCG Observatory would cause us to relocate the observatory farther away from them and the house. This past month we took the first step in building The Serenity Imaging Platform, a small 4’x4′ Observatory that would be used for remote imaging.

Starting with deck blocks on gravel on limestone rock, built up with 2″x8″ joists and a 7/16″ OSB floor, walls and roof.
Walls were 2″x3″ framing on 24″ on center. The dual doors on the south side had reinforced framing of 2″x4″ and the top of the walls had an additional 2″x3″ top plate. Doors were 2″x3″ and 7/16″ OSB. In both the roof and door cases, the OSB was overlapped against the other portion to provide no gaps.
support arms for the roof were 2″x2″ and ropes are used to open each side of the roof. One side of the roof is longer than the other and overlaps it.
In addition, pipe wrap was installed on the top roof edge, to protect the exposed OSB and also to seal the roof gap better.
After a noreaster storm pushed some rain into the gap between the roof and wall, we added a strip of 4″ flexible weatherstriping to stop that infiltration.

Power (110vac) and data (cat6 ethernet) was buried to it from the nearest source and it has now had 3 days of imaging platform commissioning.. another few sessions and it should be operational! Two coats of paint were applied to the outside of the OSB. We are considering painting the inside as well, especially the floor, to protect the OSB against moisture, dew especially.

The last many months have seen a decided lack of imaging and astronomical observing. It probably all started when the 16 year old wooden pier was removed as it was rotted, and then even more when the SCG Observatory roof blew off. Since that time the SCGO has had a new better roof installed and an interior renovation.

In the meantime, plans continued for a new imaging platform, The Serenity, further out in the back yard away from all of the tall trees. It started off as a full blown observatory but over time shrunk down to a 4’x4′ remote imaging platform only. It was completed a couple of weeks ago, and a RASCKC telescope was put in for configuration. It too has been packed away for some months.
Last night was the first time there was time available to align the telescope and see how the new handset behaved. First off, it behaved wonderfully. Buttons pushed were recognized, as opposed to the old handset (15+ years old) which did not work well at all.

It was a little difficult to squeeze into the observatory with a diagonal and an eyepiece to do the alignments but in the end, Arcturus and Altair were centered and off we went to Jupiter with a camera installed.

All in all not too bad. An hour or two prepping and then waiting for dark, waiting for stars to come out, waiting for clouds to pass, and a rough alignment was completed.

In the next 15 minutes I managed two 30 second runs of Jupiter, one 30 second run of Saturn and two 30 second runs of the Moon. Unfortunately Mars was behind a different large tree 🙁
The mosquitos were bad and once the alignment is finalized, I should be able to remote the imaging platform from somewhere inside, away from the bugs.

Firecapture was used with a ZWO ASI 120MC camera. I have successfully used Handyavi and its telescope interface successfully to control the telescope from the computer and not the handset, but it was not working last night. So all telescope control was using the new handset. Pointing was not great but got close enough to find the target. The microfocuser worked well.

The 30 second .avi files were processed with autostakkert! v3 and then with registax for RGB balance and wavelet processing.
The images looked pretty soft and fuzzy after autostakkert and only the registax wavelet processing really brought them into their own, sharper and better focus and contrast. My image annotation linux scripts were not applied at this time as I have forgotten how to apply them correctly.. another thing to catch up on.

Jupiter was low in the southwest, an altitude of 25 degrees. This first image was exposed at 6ms and is incorrectly oriented as I have forgotten the optics of the Schmidt Cassegrain with a diagonal and a camera orientation. This is the best 50% of the frames.

The second image was taken right after the first and was 8ms exposure, 30 second run and the best 50% of the frames.

These two images of Saturn were 47ms exposures over 30 seconds and the best of 25% and then 50% of the frames.

Lastly the Moon:

2ms exposures on a 30 second run on Mare Crisium and Crater Proclus. The orientation appears to be correct.

The last image of the night of the Mare Imbrium Sinus Iridum Crater Plato area, 2ms over 30 seconds and the best 50%.

There is a long TODO list to accomplish this evening before dark:
add velcro to the handset so it can hang off the mount rather than hang down in the air and floor
cable management to get them off the ground and not underfoot
add weatherstripping to the roof/wall interface as some rain blew in during the last storm
build a dew shield as the corrector is bare with no heating at this point
add the telrad dew shield built earlier this month
attempt an alignment using the camera only not the eyepiece. This would be more accurate as it is at a much higher apparent magnification.
If successful, remove the diagonal.
Simplifying the optical path is always a good thing. This removes another optical flip, removes another 5-15% loss from the diagonal mirror reflectivity, and more.

This weekend: varathane the OSB floor as I keep tracking in water from wet boots.
For the ZWO ASI120MC camera pixel size, a focal ration of F20 is the optimum. This existing scope is a Meade LX200GPS 20cm F10 focal length 2000mm. We will add a x2 barlow to bring the F10 up to F20. This will double the size in pixels of the planetary image on the camera sensor.