Lagoon Region

Taking the AT6RC tube off and installing the Televue 76mm on the mount changes the game a bit. Lower magnification, wider field, a setup I find more appropriate for Waikoloa skies.

The average seeing in Waikoloa is 2 or 3 arcseconds, or worse… Not the 0.5 arseconds typical at the summit. This leads to mushy stars at higher magnification, fuzzballs rather than pinpoints. Lower magnification sidesteps this problem.

Still using the borrowed ASI2600MC color camera for a few more days, seeing just what it is capable of. The slightly larger sensor is nice and the data easier to process, but still I am seeing limitations that annoy me in the fine details. The color balance is difficult to deal with as well.

I will be going back to the ASI1600MM and filter wheel soon enough. I do need to up my processing game, the software side has changed substantially over the years and I need to transition. Will be giving PixInsight a spin over the next month.

The Lagoon Nebula Region
The Lagoon Nebula Region including M8, M20, M23, NGC6544, IC 4678, Bochum 14, and much more

Of Green Stars…

Wandering the sky using a telescope and a field guide published in 1844, the better part of two centuries ago, is… uhhm… interesting. In mid-April the classic winter constellations are dissapearing into the sunset, with constellations like Monocerus and Puppis well placed for observing from my driveway just after dark. On my observing table is a reprint of that 1844 field guide, The Bedford Cycle.

At the telescope in the driveway again
At the telescope in the driveway again

Working through the entries I come to the entry for a double star Argo Navis 72 P. VIII, a designation from a very old catalog. It takes a few moments research to convert 72 P. VIII to the slightly more modern catalog number HD 71176. Modern? The Henry Draper Catalog was first published by Harvard Observatory in 1918, still over a century ago.

With the HD number I can look up the position on a modern chart and spend a few moments star-hopping the Astrola to the correct star. This double star is now located in the constellation Puppis after the ancient and absurdly large constellation Argo Navis was broken up into Puppis, Vela, and Carina.

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Using the ZWO ASI2600MC Camera

Due to a plan that failed I ended up with a borrowed astro camera for a couple weeks. Since I have it I may as well play with it a bit.

The Orion Nebula M42
The Orion Nebula M42

The camera is the ZWO ASI2600MC Pro, a one-shot color camera specificaly for astrophotography. I have the ASI1600MM Pro a monochrome camera set up with a filter wheel, but have never really had a chance to use one of the modern one shot color cameras.

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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
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.

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

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.