Sunspots of May 2

Sunspot group AR4079

In my previous post, I discussed using a HyperStar lens to turn my 11-inch Schmidt-Cassegrain telescope into a Schmidt camera. And while it does a superb job at f/2 imaging, the real beauty of the HyperStar is that it can be removed again, restoring the SCT to its native f/10 focal length for purposes other than fast, wide-field astrophotography.

For example, I also enjoy white-light solar viewing and photography with my SCT. Although a large aperture for light-gathering purposes isn't required by the brilliant sun, the large aperture of an 11-inch SCT provides better resolution of fine details of sunspots compared to smaller scopes.

I bought the HyperStar and Celestron CPC-1100 from Starizona in 2007. At the time, the HyperStar was the only game in town for fast f/2 shooting through a telescope. Celestron developed their "Fastar" lens in the 1990s, but discontinued them for some reason in the early 2000s. Starizona's HyperStar is similar to the Fastar and it requires Fastar-compatible telescopes, which are still produced by Celestron. But recently, Celestron began producing their RASA (Rowe-Ackermann Schmidt Astrograph) telescopes that also offer f/2 focal ratios. 

RASA telescopes are like Schmidt cameras, where the secondary mirror is completely left out of the design and replaced with a camera (or film holder, in the case of the Schmidt cameras). So, the primary difference between a RASA and an SCT/HyperStar combo, is that the RASA is always and only an f/2 telescope. You can't replace its camera with a secondary mirror, which means you can't put an eyepiece in a RASA and do any visual observing with it. 

The RASA's advantage is its no fuss, no muss appeal. It still requires that you bring your own camera, but it's a snap to attach your camera to the RASA. You don't have to perform the scary operation of swapping out your precision secondary mirror with a lens. The RASA's lens has been installed for you at the factory, so you'll never have to.

If you can afford it, a good plan nowadays might be to buy a RASA for f/2 imaging, and then also buy a longer focal length telescope for looking through the eyepiece at the sun, moon, planets, and deep-sky objects. This removes any hesitancy about setting up your telescope for whichever type of observing/imaging you want to do. But if you don't mind swapping out the secondary mirror from time to time, the SCT/HyperStar combo gives you "one scope to rule them all." 

SCT with HyperStar (left) and full-aperture solar
 filter (right). You can't do this with a RASA!

I have to admit that I don't remove the HyperStar as often as I used to. The older I get, the less inclined I am to make changes to my setup. I don't want to break from my routine. I hunt for supernovae nightly with the HyperStar. So, when a nice sunspot group appears on the sun, like the large AR4079 ("AR" for "active region") group in my photo above, I debate with myself for a longer period now, as to whether or not I want to trouble myself with (**Sigh**) removing the HyperStar and camera, putting the secondary mirror back in, putting the solar filter on, attaching the f/6.3 focal reducer and my DSLR camera, and then sitting out there in the hot sun, using a black T-shirt as a hood over the camera to help me see the solar image better in the camera's LCD viewer, for however long it takes to get the camera focused. And, of course, afterward, I'll need to get the HyperStar and camera back on there for tonight's supernova hunting. So it's double the work, all told.

Does it really sound all that exhausting? It didn't seem exhausting to me 15 years ago. In practice, it takes all of about an hour to make all those changes, roll out the scope, grab some images until I get one that's sharp enough, and put the scope away again. No exaggeration there. Literally, no more than an hour to do all that. 

After getting the scope back inside, it needs to cool off for a while before I put the HyperStar and camera on it again. I usually wait until I set up that evening for supernova hunting, to take off the secondary and install the HyperStar. Then there's the plugging in and securing of the camera cables. When twilight falls and I get the 3-star alignment done, I'll collimate the HyperStar. But the completion of the changeover adds only a couple of minutes to my setup time. 

Still, the process of changeover from HyperStar to solar filter and back causes me to think long and hard about it, before I decide to go out at mid-day and shoot the sun.

I don't know what's going on with my brain. Is this an old-guy thing? It's like ordering a computer desk or a bookcase from Wayfair. You know, when the box arrives, you look at it and go, "How'd they fit that desk into such a small box?" And the thoughts of opening the box, finding the instructions, making sure you got all the pieces, gathering all the tools, clearing out a large enough area in the room to lay everything out and begin assembling it — man! It's just overwhelming to me now. I'll likely just lean the box up against the living room wall for a few weeks until I feel like assembling it. I didn't used to be that way! I used to love tearing into a complicated assembly. I couldn't wait to open the box!

And I suppose it's the same way with my telescope setup. During the first few years of using my CPC-1100 and HyperStar, I carefully stored it in a closet after imaging. Whenever I wanted to use it, I had to first take the telescope apart into two manageable pieces (fork-arms assembly and tripod), round up the focuser, camera, HyperStar, and laptop, and then carry it all outside where I'd assemble it. After each use, I put all the small pieces into the plastic bags and little boxes that they came in. I'd take off the camera and put it into a box. I'd pull off the HyperStar and put it into its Pelican case. I'd reinstall the secondary mirror and then put the lens cap back on the front of the SCT. That was a lot of tedious work that I didn't mind doing each and every night!

As a matter of fact, I felt that I must do it that way, because all of it was new and fairly expensive. I wanted to take good care of it and keep the optics dust-free.

But you know what I found out? First of all, a little bit of dust doesn't matter! No, actually, a lot of dust doesn't even matter! I notice no appreciable difference in my images whether the corrector plate is clean or dirty. More importantly, I've learned over the years that it's the daily plugging and unplugging of cables that makes their connectors go bad. All of a sudden you plug in the focuser one night and the software can't detect it. Or, all of a sudden, the power on one of your devices becomes intermittent because the power cable is worn out from wrapping it up every night and putting it back in its box. Or the cable connector starts to frequently fall out of one of your devices on its own. Cables and connectors are the weakest link in the chain of these systems. It's better to plug them in once and then leave them plugged in! It's much better for the system to not take it apart and put it back together every night. You will have much less down time if you leave things connected. I was keeping notes and writing down each time that I had to recrimp a new set of connectors onto a telescope or focus cable. And then it occurred to me that if I just stop this unnecessary assembly/disassembly on each outing, the cables and connectors will last much longer!

Nowadays I leave my scope assembled all the time. I don't even bother to cover the SCT corrector plate anymore when not in use. I clean it off about once a year, or whenever I can no longer stand its dusty appearance! The scope is, after all, more than 18 years old. I've set it up and used it for imaging on over 2,600 nights since 2007. I no longer worry about the wear and tear of daily use. I don't try to keep it looking shiny and new. I just roll the scope back into the shed on its Scopebuggy at the end of the night and leave it there until the next night. No removing things and putting them back into their plastic bags. No unplugging the cables and putting them back into their boxes. 

The only two cables that I wrap up (loosely) are the 25-foot extension cord that I plug into the telescope's secured power strip, and the 100-ft Cat-5 cable that I stretch across the yard each night so that I can control the laptop from my living room during imaging sessions. Also, I do unplug the USB cables from the laptop, but I leave the other ends plugged into their associated devices. I have found that a certain order is necessary during power up and if I leave all the USB cables plugged into the computer, the software sometimes gets confused as to which device is which! To eliminate wasted time to troubleshoot "device not found" messages, I follow a strict order for plugging in USB cables during power up and I never have any issues when I follow the correct order. 

So, when I was younger and wasn't overwhelmed at the thoughts of taking the scope apart at the end of each night and putting it back together on the next night, I was sort of doing myself a favor. That is, if a nice sunspot group appeared at some point, my SCT was put away with its secondary mirror in place. It was ready to go for solar imaging, if I wanted. I didn't have to worry about the process of swapping out the HyperStar and camera. But now in my old age, after getting used to not disassembling my scope before putting it away in the morning, I find myself feeling less motivated to pull the switcheroo for solar imaging.

I did not, however, intend for this post to be a debate about whether an SCT/HyperStar combo is better than a RASA. Nor did I want to get caught up in a discussion of the differences in motivation between youth and old age. I really just wanted to highlight the fact that, as backyard telescope enthusiasts, we can develop multiple interests in observing and imaging, and because of that, we require multiple instruments and/or multiple telescope configurations.

Sure, my primary interest is supernova hunting. For that, my SCT/HyperStar combo has proven to be the perfect telescope configuration. A large aperture and fast focal ratio make it possible to take short exposures (20 seconds) of galaxies and detect supernovae down to 17th magnitude. And taking short exposures means having the time to shoot more galaxies each night. Shooting more galaxies each night is the key to finding supernovae. That's a slam dunk. But I also have a keen interest in other celestial objects that look better without the HyperStar. 

The sun is an interesting target. It's technically the closest star to earth. So, we telescope enthusiasts have a unique opportunity to observe our closest star with high power and solar filters and witness sunspots, solar flares, and prominences. This requires different instrumentation and filters. But our sun is the only star we can observe like this. All the other stars in the Milky Way are too far away for high-power views. No matter what telescope we have, or what magnification we use, all the other stars in the Milky Way look like mere pinpoints of light in our telescopes. We can't, for instance, zoom in on Sirius or Vega with our telescopes and see their sunspots. We can't resolve them into disks like my picture of the sun at the top of this page. No, even at the highest magnification we can use in our telescopes, Sirius and Vega still look like they do to the naked eye: just pinpoints of light. Only they're much brighter pinpoints when we look at them through our telescopes.

I also enjoy looking at the moon and other planets in our solar system. These objects really benefit from higher magnification. SCT/Hyperstar combos and RASA telescopes don't perform well on the moon and planets, because they're designed for low-power imaging and you can't change their magnification. But the moon and planets offer many more observing opportunities than the sun. And I can't be bothered to switch out the HyperStar every time I want to have a look at lunar craters, Jupiter's moons, or Saturn's rings. I simply must have in my arsenal a second telescope with which to look at those objects, even while my SCT and HyperStar are taking images of galaxies in my supernova searches.

The planet Uranus was in the same field of view as
the totally eclipsed moon on November 8, 2022.
HyperStar and DSLR; 2.5 seconds at ISO-200

Oh, yeah! I almost forgot. There is one very good occasion to use the HyperStar on the moon: during a total lunar eclipse! The moon becomes a rather low-light target during maximum eclipse, requiring astrophotographers to increase their exposure times and ISO. Longer exposures have a risk of motion blur from atmospheric smearing when using moderate magnification. And increasing the ISO can make the images noisy. But low-light shooting is what the HyperStar was designed for. I found that the HyperStar can deliver crisp, bright images of the moon, while also pulling in background stars, even at low ISO.

A good 4-inch APO refractor serves well as a second telescope. Even better is a larger-aperture Dobsonian. On warm summer nights, while I'm searching for supernovae with the SCT, I love to set up my 10-inch Dobsonian and take some breaks from supernova hunting to go out and look at my favorite Messier objects through the Dobsonian, or watch Jupiter's moons and their shadows cast onto Jupiter's disk, or see if Jupiter's Great Red Spot is visible, or have a look at Saturn's rings and moons. Splitting tight double stars is also a fun activity, or viewing carbon stars (stars with a deep red color). 

There really isn't such a thing as "one scope to rule them all," because sometimes we require two telescopes at the same time.