Equipment

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My setups along the way. At this point, I have sold off the Dobs and only only use the leftmost setup.


My current setup: TS Optics 80, ZWO ASI533 on Sirius EQ-G mount; Orion 50mm scope and Asi120mm for guiding.

My prior setup: Orion ST120 achro, Canon 1000D on Sirius EQ-G Tracking/GoTo mount.

My first scope: Orion SkyQuest XT8, a classic DOB. It is a great starter scope: highly recommended.



The Orion XT10 with Intelliscope. The monster! My brother calls this the human catapult. Got this after the XT8

The Orion ST120 on small equatorial mount. Got this when I restarted astro in 2017. This is not GoTo so you have to find DSO manually.


The astrophotography setup is much more complex than I imagined. Some pieces are obvious (telescope, camera) but it turns out that just gets your first snapshot... and it takes a lot of equipment to get from that first snapshot that looks crappy to something you would actually show other astro folks.

Here is some info on the pieces of my setup.

Mount


The mantra in AP is that the three most important pieces of equipment are the mount, the mount, and the mount! Seriously, the most consistent recommendation is to get the best mount you can afford. After doing this for a bit, you realize that it does make a difference, as the mount is what keeps the telescope exactly trained on the object you are trying to image. To do this, it is actually rotating to match the rotation of the earth and it needs to do this pretty precisely. (For reference, if you do not have a tracking mount, with my telescope you start seeing star trails in under 2s).

I have the Orion Sirius mount which is equivalent to the more common Skywalker HEQ5 mount. It is near the bottom of what is required for AP but still decent for the size telescope I have. In retrospect, I definitely should have paid a bit more and gotten the one grade up of Orion Atlas aka HEQ6, but I was worried about the weight of that for lugging from garage to backyard. In the end, lugging a mount at all (mine is over 60lbs) is too much of a pain so I got a weatherproof cover and the mount stays outside. So it didn't matter at all that the HEQ6 is extra heavy and I am now stuck with a less than ideal mount. Oh well... Live and learn.


Telescope


My telescope now is the TS Optics Photoline 80mm. Getting this scope to replace my Orion ST120 achromat was, unfortunately, a long saga. First, the scope was backordered for 4 months. Then, when it arrived, I noticed problems with stars in the image. I tried to fix based on instructions from the vendor but while that helped with the original problem, it caused a different problem that required me to ship the scope back to Germany for repair. It then took another 2 months to get it back. In the end, I am happy with my scope, and it was significantly cheaper than my first choice.

The TS80 is an FPL53 triplet apochromatic. This is actually a generic scope design with many different brands selling a version of it. The TS Optics brand is from Teleskop-Express in Germany. The FPL53 in my version indicates the type of glass for the objective: this is considered the top end with highly desirable diffraction characteristics. The triplet denotes that it actually has 3 lenses which allows it to bring all three primary colors (red, green, blue) into focus simultaneously to a single plane. In theory at least, this should result in pin-point stars compared to the blue-halo'd blobs I had with my achromat. Additionally, I have the TS frame flattener which improves the shapes of the stars towards the edges of the frame.


Camera


For the first several months, I just re-used my Canon 1000D DSLR as my imaging camera. This was fine and I was happy with the pictures, but in June I upgraded to an astro-camera, the ZWO ASI533MC-Pro. This camera is "cooled" which means that it has a cooler (TEC) that is able to maintain the sensor at a stable (low) temperature. There are several advantages to this over the DSLR. For one, the amount of read-noise is dramatically lower. For the summer months, in particular, the read noise is supposed to be 5x less than on my Canon. Second, since it can be set to a specific temperature, I will only need to create/use a single set of dark frames. This might seem like a small thing but every manual step I can eliminate from the process reduces the friction of imaging. And finally, since this is a astro-specific camera, it is sensitive to the Ha wavelength common in certain emission nebula. This should produce far better pictures of these types of targets.

There are a couple of downsides with this camera, however. First, it is a smaller sensor than the DSLR. The Canon sensor is a APS-C size which is quite big and covers most of the field of view of my scope. The IMX533 sensor in the ASI533 is significantly smaller so it cannot fit some of the larger targets such as Andromeda Galaxy. The second disadvantage, in my eyes at least, is that it is a square sensor. While this is a actually good thing for framing targets, it looks incongruous in that we *expect* to see rectangular images. While there is another camera with this sensor in a rectangular form factor, it is double the price and out of my budget range. Cost/benefit overall, I think this will be a much better fit for my setup.


Guiding Scope & Camera


This is my set up of guide scope (Orion mini 50mm) and guide camera (ASI120mm). Despite what I said about the mount doing the tracking, the mount itself has tracking error which will typically make exposures over 30s (depends on some other parameters but about this for me) impossible. The guide scope/camera is controlled by some guiding software (Phd2 in my case) to correct errors in tracking and allow longer exposure times without blurring.

The basic idea behind guiding is simple, but the fact that it all works is amazing. Essentially, the idea is that stars are not supposed to move. So if the guiding system is taking pictures of stars, and the stars move, then the tracking must be off and needs to be corrected. The mount moves in two axes, the right ascension (RA) and the declination (DEC) axis. The guiding system takes a periodic exposure (every 2s in my setup), calculates the error in RA and DEC based on how far the star "moved", then sends an RA and DEC correction pulse to the mount. The end result is that my mount now tracks to about 2 arc-sec total error. Since each degree is 60 arc minutes, and each arc minute is 60 arc secs, the end result is that my setup points my telscope in the sky to a precise location with an error no more than 0.001 of degree!


Capture Software


For image capture, I use NINA. This excellent open source software handles all aspects of capture process which includes controlling the mount, the camera, the guiding, everything. Much of this is done by underlying external tools but it provides an nice, clean integration on top of it all. It is a remarkable bit of software that is as full featured and stable as the paid alternatives. This might appear to be a minor aspect of imaging because, frankly, one could manually position everything and take the pictures. However, I am lazy and significantly reducing the friction involves automating as much of this. For this, NINA with the new advanced scheduler shines for me. All my equipment is supported and it effectively supports all the types of operations I use. This gets quite complicated at times. As an example, my standard sequence involves waiting until time and when target is above my customized horizon, skewing to the target, centering by plate solving and syncing to the scope, starting guiding, taking repeated images while periodically checking centering and guiding, and continuing until a time or target drops below customized horizon.


Processing Software


I use PixSight (PI) software for both the pre-processing and post-processing of the images. In the pre-processing steps, the raw images are calibrated and registered. The calibration steps try to account for the physical realities of the sensor and telescope which causes noise and vignetting of the image. The registration steps align the images so that the stars are in the same spot in the image. Once this is in place, you can then "stack" all the images which essentially averages all the raw images. The benefit of this averaging is that it greatly increases the signal-to-noise ratio of the images that allows further processing. In the post-processing steps, the image is "pulled out". The starting image looks basically all black. The post-processing is what balances the color, stretches the image to bring out the constract, along with various noise reduction techniques to clean up the image.

There are a variety of software tools can be used for this pre-processing and post-processing. For the post-processing, the most widely known would be PhotoShop (PS). All of the post-processing done in astrophotography (AP) can be done in PS and indeed many AP'ers use it. For me, PI is specifically geared toward AP and since I wasn't familiar with PS to start with, jumping directly to PI was a better choice. For pre-processing, the calibration and stacking are essentially AP only processes and not used in typical photography, so all tools here are AP based. But there are several options here including the excellent free software Deep Sky Stacker (DSS). I initially started with DSS but once I bought PI, since it includes pre-processing, I do it all with PI.