Equipment

February 16, 2025

New Tool, a Powerful Dell Precision 7875 Workstation

Workstation computers from Dell are really well-built and come with excellent next-business-day onsite service. I have been using them for a couple of decades for my work. My previous workstation served me well for almost nine years—these kinds of computers do not age as fast as normal consumer PCs.

My old Dell workstation has two ten-core Xeon processors, 128GB of memory, and a decent graphics card. Since I work with 4K and 8K videos, 3D graphics, and run AI locally, my old workstation has become far too slow. It goes to my observatory computer, little overkill for telescope and camera control but works well there.

The new Dell Precision 7875 Workstation features a 96-core AMD Threadripper Pro processor (3.2 – 5.1 GHz), 512GB of RAM, and a 20GB NVIDIA RTX 4000 Ada graphics card. It comes with a standard three-year next-business-day onsite service in case anything goes wrong.

My new display is also from Dell—a 40-inch 21:9 curved Thunderbolt hub monitor with a stunning 5K resolution and a 120Hz refresh rate. The curve in the monitor is perfect for correcting perspective distortion, ensuring that straight lines remain visually straight.

I also use an Ergotron monitor arm, so no desk space is wasted, allowing me to position the large display at the optimal distance and orientation with ease.

Secondary mirror focuser. Note a curved vane for the flat power/data cable, no diffraction spikes! The focuser is made all aluminium, it's really robust and easy to collimate.

Bended Knee Pillar angle at my location 65 degree North. Counter weights are stainless steal weight lifting weights. (~35kg)

The 14" Telescope barely fits to my SkyShed POD.

Telescope elements labeled.

QHY Polemaster, lens cover removed and ready for the action.

A steel bowl glued over the hole in the lens cover.

September 28, 2024

New setup for my astronomical nature imaging work

I haven't publish much new images in past two three years since I have had some health problems. Now I'm good as new and can start working again. Past two years I have been slowly building a new imaging platform. I have done some shorter focal length work past six years, now it's time to go closer again.

Optics

System is build around Celestron EDGE 14" telescope, I selected this scope due to its light gathering capacity, 356mm diameter and 3910mm native focal length (This very large and heavy 0.7 Reducer is especially made for the EDGE 14") One main difference to normal Celestron EDGE telescope is that I have added a secondary mirror focuser (by Optec) to get rid of a mirror flop. It can be a problem, especially with a heavy mirror. Bottom line, this scope has an excellent optical quality. There is some optical analysis and a single full scale 20min frame at end of this post.

In future I can add a "HyperStar system" to replace secondary mirror and use this telescope as a fast f2 astrograph.

Mount

I ended up to a MESU Mount MARK II since it has 100kg capacity at imaging work with a periodic error less than 4 arcseconds peak-to-peak, impressive numbers indeed. It also has zero lash back due to its friction drive system. One of the nice features is the 80mm diameter channel for all of the cords, trough the Ra and Dec axes, no more dragging cords!

The pillar I ordered with the mount is bended knee pillar type, no meridian flip is needed and telescope can track whole sky without stopping. The pillar came in easy to handle parts and assembly was very straight forward, the assembled pillar is very rigid under the weight of heavy telescope, counter weights and accessories.

Mesu mount is absolute beautiful engineering work. Support from manufacture is also very good. I had some minor problems with settings at first but they get solved in no time after we went it trough with remote connection, while on site. Bottom line, money wise this mount is a real bargain, if compared its features to any other brand or model of mount.

Camera

The Main camera is a "new" Apogee Alta U9000M with Apogee Filter wheel. It's a second hand camera originally used for the microscopic work and it looks like a bran new. There wasn't any mechanical shutter but I moved a shutter from my old Apogee Alta U16 to this new camera. (My old camera died to an old age). The camera has 12 micron pixels, it's a perfect match to this optical configuration giving an image scale of 0.91 arcseconds per pixel. The full image spans 46.1 x 46.1 arcminutes of sky. (One degree is 60 arcminutes and Full Moon spans around 30 arcminutes of sky).

Instrument rotator

At first time I have added an instrument rotator to the imaging path. I haven't use any rotator earlier since there is always some flexure.

The Wanderer Astro Rotator Pro has absolute zero flexure by the manufacture. I was very skeptical to this since if it moves, it will flex. It turned out, that there is a patented system based on neodymium magnets around the light path holding everything tightly together when rotator moves. 

After measuring carefully everything with the CCD-inspector software from test exposures under the starfield I can say, it really has no flexures at all. It's only 18 mm thick and fit to my limited back focus nicely. The rotator can handle flawlessly all the heavy load I have placed behind it.

Active optic unit

Maybe an overkill but I have added an active optics unit to the light path. It's SXV-AO from Starlight Xpress UK. I have had really good experiences doing long focal length imaging with AO unit during the years. It doesn't correct the actual seeing so much but it corrects every small or big error from heat bubbles and vibrations from heavy traffic, wind, etc. and it does that really really fast. 

It's as easy to use as any OAG, especially after I had an instrument rotator. With 14" scope, I can guide around 10 HZ by using mag 11 guide star. The MESU Mount is really good but there is lots of mass to move when guiding corrections are made. With AO there is just a small refracting glass element to move instead of telescope and heavy accessories.

Data & power box

An other new accessory is power and data box from Wanderer Astro. It makes the system less chaotic with all the data and power cords. Also controlling power and data connections can be done remotely in one software. It can handle nearly 20 amp at peak power.

Dew buster

There is also my old Dew Buster installed to the telescope. it can keep the temperature just little over the dew point, this prevent the heat current. Raising warm air inside the tube will ruin the image, if heater is even slightly too warm

Fan

I added a 70 mm computer fan to the telescopes air went to reduce the cool down time. There is an air filter in the went to prevent the dust getting inside the OTA. I can control the fan speed by the Power Box software.

QHY Polemaster

This is a new addition too, I was amazed how easy it was to use. Polar align took maybe 15 min and it's easy to redo at any time needed. here is a review about this little helper.

Lens cover

As a last item here is a lens cover for Celestron EDGE 14" telescope. It's a simple and a must accessory to prevent dust in the collector lens. How ever, in my case there is a secondary mirror focuser sticking out and it prevents to use the standard Celestron aluminium cover over the telescope. 

I solved the problem by cutting a circular hole in the lens cover. After that, I bought a steel bowl from local market ( it was just 5 € or about 5 $) I sprayed it matt black and glued it to the cover with an elastic, rubber like, superglue.