Astrophotography – Page 2

A Bahtinov Mask for the TeleVue 76

For some reason I have gotten along without a focus mask for the TV-76. Need to fix that… Done.

A 3D printed Bahtinov focusing mask for a Televue 76mm telescope

Just a quick project, about half an hour to design and four hours printing. First print a pleasing success, a completely functional part.

A Bahtinov Mask is used to get a precise focus, something I wrote about a few years back.

For this mask I used a public bit of OpenSCAD code from Jens Scheidtmann to generate the mask pattern, just tuning it for the correct sizing and performance with the TV-76. I added my own version of the support collar, making it a bit neater with fillets and properly sized to slip over the TV-76 glare shield.

You can download the SLT file for the mask from Cults3D if you need to print your own.

The part is one of a half dozen parts I have designed and printed over the last few weeks to reassemble the photo rig. A new guide camera mount, a mount for the ASI Air computer, a new glare shield for the guider, etc., etc… The utility of 3D printing a game changer for me.

Comet C/2022 E3 ZTF

A spate of bad weather followed by the bright moon kept me from imaging the comet until this week. A little late to the game and a fading comet. Still, I did get an image.

The comet is currently high in the evening sky, an easy target. An now that the bright Moon has left the evening sky this week and next represent a last chance to see the comet before it truly begins to fade.

Comet ZTF has faded below 6th magnitude according to recent estimates, too faint for the unaided eye, but still spottable in binoculars and fairly easy to catch in a small telescope. The comet remain well placed to spot for some time to come but will slowly fade, dropping to about 8th magnitude by the end of the month.

Canon 6D with a TeleVue 76mm scope riding on an ZWO AM5 mount. 30 x 180s images processed in DSS. A version processed to remove stars does show a trace of the ion tail.

Comet C/2022 E3 ZTF no stars — Comet C/2022 E3 ZTF with stars removed

A Not Quite Total Lunar Eclipse

Normally when I see a partial lunar eclipse on the calendar I do not take much note. As a partial will not create the deep red Moon that makes a lunar eclipse so striking, it is not something that I usually make a point to view.

This eclipse was a bit different. As this was a very deep partial, only a few percent of the Moon remaining in the sunlight, it should look pretty good… And it did. I setup the little TV-76mm scope to snap a few photos.

Even a not quite total lunar eclipse can be quite nice. Since this eclipse occured just a few degrees from the Pleiades star cluster it was possible to frame both in the camera with a wider field of view. Thus I changed to a classic 100mm f/2.8 Canon FD lens to shoot a few of the cluster and the eclipsed Moon.

Of course this means I will get to sleep at midnight and need to get up at 5am for work. The price I will pay for staying up to watch an eclipse.

A deep partial lunar eclipse and the Pleiades star cluster

NGC6888 in Hydrogen Alpha

NGC6888 The Crescent Nebula in Hydrogen Alpha — NGC6888 The Crescent Nebula in hydrogen alpha

M33

The Triangulum Galaxy, M33, 15x120s exposures using a Canon 6D and a TV-76mm 'scope — The Triangulum Galaxy, M33

The North American Nebula

NGC7000 or The North American Nebula is found in Cygnus, just northwest of the bright star Deneb. A huge complex of glowing gas and dark dust the nebula covers and area several times larger than the full moon.

The image here is the sum of 60 individual frames, 30 at 1 minute and 30 more at 5 minutes of exposure taken with a TeleVue 76mm scope and a ZWO ASI1600mm Pro camera through a hydrogen alpha filter.

The bright North American Nebula and the rifts of the dark nebulae LDN 935 in hydrogen alpha light

Chasing a Comet in the Dawn

Comet C/2020 F3 NEOWISE

A Bright Comet in the Dawn

We have a bright comet in the dawn sky for a few days. Comet C/2020 F3 NEOWISE has brightened rapidly over the past few weeks, now about 1st magnitude it can just be seen against the glow of dawn.

I took along Hodepodge to serve as a tracking mount for the TV-76mm scope and a couple cameras to do some comet shooting. The Canon 6D would go with the small ‘scope, the EOS-M5 with a tripod for wide angle shots.

Driving up Waikoloa road I was troubled by a bank of clouds in the Waimea saddle, thus I elected to head for the Humuʻula saddle instead. I ended up in the lava fields along the Mauna Loa access road. The view was perfect, and I had just enough time to get the mount and camera setup as the comet rose.

The Veil in Hydrogen Alpha

To allow a wider field of view requires changing optics. In this case putting away the TV-76mm telescope and mounting a vintage Nikkor 180mm f/2.8 ED camera lens.

The Nikkor 180mm is a classic lens, once a favorite of professional film photographers for news and portrait work. Now the lens is out of date, not autofocus, or image stabilized, a bit of very good optics left behind by technology.

Of course, autofocus or image stabilization are useless for astrophotography. With a simple adapter the lens can be mounted to a modern system and used as a fully manual lens in an application where the excellent optical quality can still be appreciated.