The Scruffy Astronomer

An astroterrestrial photo is one that includes a star field as a background with something in the foreground to provide a subject. It can be a tree, a building, or anything the photographer chooses. In this case it was James. James lives in Canberra, and last May, was celebrating the end of the local lockdown with a weekend at Lake Eucumbene with his girlfriend Loz. James normally takes deep-sky nebula photos, so he took a 12" go-to Dobsonian with him, which is quite a task. His intended targets were the Lagoon and Trifid nebulas, which were rising just after midnight. But setting up, he found that they weren't high enough to be much good. For targets near the horizon, you're looking through the boiling, dust-ridden soup that is the Earth's atmosphere. It wasn't until 2am that a photo was possible. But at that point, the dew was getting heavy and the secondary mirror on the Dob was starting to fog over. Such is life for the astrophotographer. The night wasn't a...

"I can't see anything" This is one of the most common comments - actually, probably the most common comment I get when doing telescope support. Whenever I hear this, my heart sinks a little. It's never a good thing that someone is having this amount of difficulty. There's a danger that I'll lose this person. The other thing is that such a comment doesn't give me anything to work with. it's my job to solve this person's problem, and I've got nowhere to start. In this particular instance, I was chatting with an astronomer who had just got a CMOS camera onto to his scope. He'd got the computer connected, and had checked it was giving him an image (he'd shone a torch down the scope and the screen had gone white). But all he could see was a black screen. This is how I got him going again. Invisible stars Out of focus stars look black. It's not that they're not there, or underexposed, it's just that they're so diffu...

I've mentioned the dwarf planet Ceres in my posts before, but only in passing. it's a little hard to introduce Ceres, due to changing nomenclature. It used to be considered the largest asteroid, but it's now called a dwarf planet. It's certainly the largest object found in the asteroid belt between Mars and Jupiter. It's also the only defined dwarf planet this side of Neptune. We've known about Ceres since the start of the 19th Century. Astronomers had been looking for planets between Mars and Jupiter, and discovered a number. They called this group "asteroids", meaning things that are "almost, but not quite, entirely unlike stars". But the thing that's most interesting about Ceres is those white dots. Hubble got a few photos of odd bright patches on Ceres back in 2004. Aliens? Yeah, naah. The Dawn mission, when a probe orbited Ceres, found that these were patches of sodium carbonate. These had probably formed when salty water bubbled up ...

Ceres - but what is it? I've mentioned the dwarf planet Ceres in my posts before, but only in passing. it's a little hard to introduce Ceres, due to confusion over nomenclature. It used to be considered the largest asteroid, but with all the debate over asteroids and dwarf planets, I really have no idea what I'm meant to call it. It's certainly the largest object found in the so-called "asteroid belt", but also the only defined "dwarf planet" found this side of Neptune. Apart from that, well, frankly you can call it what you want in this post-modern world. Discovery We've known about Ceres since the start of the 19th Century. Astronomers had been looking for planets in the zone between Mars and Jupiter. Kepler had noticed this gap was large enough to contain a planet, but didn't seen to have one. Following a search, astronomers discovered a number of objects. They called this group "asteroids", meaning things that are ...

An unusual Barlow that's shipped with (at least some) Celestron StarSense Explorer telescopes has to be assembled in an unusual way in order to be able to focus on stars. We’ve been selling the new Celestron StarSense Explorer telescopes for a few months now. The StarSense Explorer is a nifty new development in the world of beginner to intermediate telescope mounts. It uses the camera on your mobile phone to determine which way the scope is pointed by looking at the stars and consulting a database. It then guides you to whatever you want to look at. Very clever. Of course, our stock sold out before we were able to grab one to use as a display model, so I still have yet to play with one. But that’s not the point of this post. The point is the strange Barlow lens that comes with the StarSense Explorers. A Barlow is inserted into the converging rays of the telescope, making them converge less. Put simply, this pushes the focal point (where the light actually converges) further back fr...

I know that for a lot of you, microscope photography is second nature, but being the astrophotographer, I'm working at the other end of the spectrum and this is something that's new to me. We sell a range of microscopes. They start as very basic microscopes - essentially for kids and students, and go up to what I might call a middle-range professional instrument, suitable for engineering laboratories, vets, botanists, pest controllers, etc. Nothing like cutting-edge university labs or electron microscopes, sorry. We've also got a number of ways of getting an image from a microscope. We'd prefer to use a separate imager, which is essentially a camera sensor that slides into the eyepiece holder or trinocular head.  We've even got a few entirely digital microscopes, both hand-held or with a screen on a microscope body. If pushed, we can even get a mobile phone camera to the eyepiece. But the other day, a customer asked about how to attach a DSLR to a microscope. I'...

Terrestroastropho... whaaa? No, it's not really a thing, it'd be more like astroterrestrial photography. It's that branch of astrophotography where you use some terrestrial feature in the foreground and stars in the background. Being a nebula guy, I'm no expert at this, I assure you. This is pretty rough, but it'll get you started with some ideas. This was back in January 2017, and we were down at Sorrento with the family. It was a pleasant time, pre-Covid. On one of the evenings, my daughter and I went down to Diamond Bay to get some shots. We were looking North a half hour before midnight. You can tell that from the stars. This is a single 30s exposure, f/3.5 at ISO 3200. I had a Pentax fish-eye lens, which I don't like much. You can see horrible chromatic aberration if you look closely at the brighter stars. I used no tracking, just a tripod. I wanted to keep it as simple as possible. In fact, if you really want to go basic, you don't need the tripod, ju...

Over the last few weeks I've posted about a few star clusters. These are groups of stars you can see using an inexpensive telescope from the suburbs while you're under lockdown. Here's another one. This cluster was named after its (supposed) discoverer, the ancient Greek astronomer Ptolemy. It's in all sorts of catalogues, including Messier's catalogue as M7 and the New General Catalogue as NGC 6475. You don't actually need a telescope to see this one. A pair of binoculars will do, because not only is it made up of nice bright stars, it's also quite large. In fact, if you're in a dark sky area, you might see it with your naked eye. The cluster itself is just outside Scorpio. This is a very recognisable constellation that's rising in the East in the evening at this time of year (July). I always think that it looks like a gigantic backwards question mark. I've attached a screenshot from Stellarium, but of course you can use your own: there are lots...

5 August 2020 People have sometimes asked me why they can't see a planet as a big round image that nearly fills the field of view. Sometimes, they've got quite cranky with me, convinced that either the telescope is faulty or that they've been sold something that doesn't do the job. The first part - that the telescope is faulty - is not the case (well, I guess there's always the possibility that the telescope really is faulty, but that's a warranty issue). The second part - that they've got the impression that the telescope they're buying would give them gigantic image - may be fair. Customer expectations It's very common that people come to the store looking for a telescope that can see the planets. Most of the time, it's for their kids. These people have normally been on the website and found a telescope like a 60mm refractor with a 700mm focal length. Alternatively, they've found a reflector, something like a 76mm aperture and...

This is what you can do with a small star tracking device. Steve from Tassie recently got himself a Sky-Watcher Star Adventurer, which is like a small equatorial mount designed to carry a camera and normal lens. Steve used his Lumix G9, a micro four-thirds camera with a 200mm f/2.8 lens. This gave him the equivalent of 400mm focal length for a full frame. Using ISO 1250, he took 12 30 second exposures, which he stacked using Affinity. Final touches he did in Apple photos. As to the photo, it’s one of my favourite areas in the sky, the end of the Rho Ophiuchi dust trail. There’s so much there. Just for fun, I've put an annotated version of the photo at the bottom. The bright yellow star is Antares, the eye of the Scorpion. Above and to the left is the globular cluster M4, but between them is the smaller cluster NGC 6144. Continuing anti-clockwise, Alniyat is next, and then the smaller star HIP 80079 to the left of the shot. Below this is (for me, at least) the star of the show, Rho ...