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Automating Astrophotography: Sequence Generator Pro Review

After many nights up late with your astrophotography rig, you may start to miss having a full night’s rest! An equipment automation and sequencer tool like Sequence Generator Pro can give you back your sleep schedule. Sequence Generator Pro, or SGPro for short, can control everything from your telescope mount to your camera to your dome, and everything in between. With the sequencer, you can run multiple targets each night with different filters and settings, all while you snooze (or do some visual observing!)

Features

Equipment

In SGPro, you can save an equipment profile with all the details for each component of your astrophotography; if you run multiple rigs, you can easily switch between equipment profiles, and apply them to specific sequence files.

Equipment Profile Manager. Credit: AstronoMolly

You can define the filters in your filter wheel, set focus offsets for each filter, choose the step size and number of steps for the autofocus routine, and more. You can connect SGPro to the autoguiding software of your choice (PHD2, Astroart, Metaguide, Direct Mount Guider if using TheSkyX, or SkyGuard/SkyGuide) so that SGPro can initiate, pause, and stop guiding as needed during the sequence. You can also connect to weather services, switches like the Pegasus Powerbox and PrimaLuce Eagle, flat panels, and safety monitors. 

Autofocus

SGPro can run autofocus for you throughout the night based on the conditions you set. It can re-focus on a filter change (helpful if you haven’t measured filter offsets), temperature change (necessary for some temperature-sensitive refractors, such as my Takahashi FSQ-106N), after a number of frames or amount of time, and after a centering action (helpful for telescopes like Schmidt-Cassegrains whose focus can change in different parts of the sky). You can also input a temperature compensation constant (steps/degree) if you have measured this value.

Autofocus settings. Credit: AstronoMolly

The autofocus routine fits a parabola to the focus points that it measures, and then estimates the minimum of the parabola. If it doesn’t find the minimum, it will move the focuser further inward or outward and try again. I have found that a parabola doesn’t always fit my focus profiles very nicely; it works well for my Schmidt-Cassegrain, but my Takahashi tends to be a bit more of a hyperbolic shape, which can cause the minimum to not be in the correct location (although this may have more to do with poor performance in estimating the half-flux radii of stars when they become too large).

An example of SGPro’s autofocus routine miscalculating the minimum focus point due to an errant star-size measurement. Credit: AstronoMolly

Solving & Centering

No more guessing and checking on centering and rotation of your target – SGPro will do that for you! With the help of a plate-solving program such as Pinpoint, PlateSolve2 (free), ASTAP (free), or astrometry.net (if you have an internet connection), SGPro will get plate-solved coordinates, slew your telescope by the offset from the plate solution to your desired coordinates, and then plate-solve a new image to check, repeating this process until a user-specified tolerance is met. If you have a rotator, the rotation angle will also be part of the centering action.

Centering action with PlateSolve2. Credit: AstronoMolly

PlateSolve2 and ASTAP are both very fast, although you must dedicate several gigabytes of disk space to their catalogs. Astrometry.net is an option, but it is very slow. Pinpoint costs $149. SGPro will initiate the plate solver with the user-specified pixel scale from the equipment profile and the desired coordinates; you don’t need to set these in the plate solver application.

Meridian Flip

The dreaded meridian flip is a work-intensive step in the imaging process for any equatorial mount user. SGPro will take this work off your hands! It will plate-solve the current location to verify the coordinates, pause the autoguider, perform the meridian flip slew, re-center the telescope using plate-solving, re-start the autoguider, and continue imaging. If you have the option ticked to autofocus after an automatic centering action, it will also run the autofocus routine.

Meridian flip routine. Credit: AstronoMolly

I have found the meridian flip routine to be very reliable. I sleep well at night not worrying about it!

Sequencer

The most important feature of Sequence Generator Pro is, of course, the sequencer! It maintains the order of the operations and allows you to image multiple targets per night.

The sequencer window. Credit: AstronoMolly

The screen is quite busy so it takes some getting used to, but this is the main command center for building your sequence. On the upper left is your list of targets. For each target, you set the celestial coordinates and rotation angle (if applicable), whether you would like the telescope to center the target via plate-solving, and the start and end times of the exposure. Coordinates can be imported using a link from AstroBin, Telescopius, or Flickr, or you can enter them manually. The coordinate boxes are pretty robust to the format you enter them in; you can copy and paste both RA and declination at the same time into the RA box, either with ‘hms’ letters or symbols, and it will convert it for you. Note that SGPro operates in the J2000 epoch, so be sure you input J2000 coordinates or your images will be off-center!

Target settings window. Credit: AstronoMolly

The “Planning tools” link opens a new window with an altitude vs. time graph for the target to help you choose start and end times. To end at dawn, you can untick the “end at” box, and set a global sequence end time in the Sequence Settings button beneath the target list.

You can specify what you would like to happen at the end of the sequence in the Equipment Profile. I have SGPro warm the camera and park the telescope (you set the park location in your mount’s hardware, or software in the case of TheSkyX).

Other Features

One of my favorite tools is the Flat Wizard, which determines the appropriate exposure time for your flat frames for each filter. You can then run flats as a sequence, and save the sequence and exposure times for later. Flat frames became a set-and-forget routine for me. SGPro also has a mosaic planner that will automatically create the targets with coordinates loaded for you for the center of each panel.

Framing & Mosaic Wizard. Credit: AstronoMolly

Drawbacks

The multiple-windowed interface and numerous tiny buttons of SGPro made it difficult to navigate at first. Understanding the difference between the global Equipment Profile Manager and the local Control Panel for a specific sequence with the same types of settings also took some time – you can have different sets of equipment settings for each sequence, which replace the global settings for that particular sequence. I also find the fact that some windows hide other windows, making it impossible to click on the windows behind them, rather irritating.

SGPro primary interface. Credit: AstronoMolly

The autofocus routine has given me a fair bit of trouble, as mentioned above. But SGPro will keep trying, which has occasionally ended in my telescope not parking by dawn when the plate solver is still trying to solve a clouded-out image (setting limits on your mount is important with any automation software!)

It also comes at a price, although it is a relatively manageable one: $149 initially, and then $59/year, which allows you to install it on three computers simultaneously (helpful for having a backup computer or running multiple rigs!). You can also choose to have as many as six installations for an additional cost.

Conclusion

While it has a steep learning curve, Sequence Generator Pro gives me freedom to pursue other activities while my astrophotography rig runs itself, including visual observing, socializing at star parties and club get-togethers, and perhaps most importantly, sleep! I have used it for about six years, but a new contender has come on the scene with all the features of SGPro but with a more-refined interface and finer control over the order of operations: N.I.N.A. (Nighttime Imaging ‘N’ Astronomy). N.I.N.A is giving SGPro a run for its money, particularly since it is free and open source. I reached out to the Main Sequence Software team, and new features are actively in development, including improvements to the target list and user interface, so we will see what new features they bring to the table. In the meantime, I have switched to N.I.N.A. in the last six months, and I prefer it to Sequence Generator Pro. 

 

MSRP: $149 initially, and then $59/year
Website: www.sequencegeneratorpro.com

About AstronoMolly

I got into astrophotography in July 2015 after receiving my first telescope as a gift. Much trial and error later, I now have three astrophotography rigs set up in my backyard just north of Berkeley, CA, in the San Francisco Bay area, including one dedicated to variable star and exoplanet transit observations. I love doing STEM and astronomy outreach, and I've accrued more than 150 hours of volunteer activities reaching over 20,000 people, both in-person and virtually. I am an AAVSO Ambassador (American Association of Variable Star Observers), an Explore Alliance Ambassador, and a panelist and broadcaster for The Astro Imaging Channel weekly YouTube show. I have a B.S. in Physics from Washington State University, and am currently pursuing my PhD in Physics at University of California, Berkeley, studying neutrinos with my two cats, Orion and Apollo.

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