Exploring the cosmos
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.
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.
A Simple Helical Crayford Focuser
How simple can a focuser be?
This has been a bit of a design challence for me… Just how small, how simple, can I make a focuser and yet still provide excellent usability. My latest Helix 1-14 design is my best yet.
As my 3D printer design skills improve I applied lessons learned and the unique capabilities of an FDM printer to the problem of a focuser. After a bit of a journey I have arrived at a design I can consider finished. Is it the final design? I may tinker some more, but I am satified for the moment.
The design is based on a few ideas from here and there, products I have seen or used, internet postings from others faced with the same challenge. I am not one for just printing someone else’s design, I rarely do that, I want to do my own, and maybe make it better.Continue reading “A Simple Helical Crayford Focuser”
Keck in the Snow
Testing a Mirror
As I have observed lately, most of the small telescope mirrors available right now are out of China, most of those produced by one company, Guan Sheng Optical or GSO. If you want a small mirror, say a 6″ or 8″ mirror, there is not a lot of choice, the mirror makers in the US generally do not do anything smaller than 10″.
The GSO mirrors range from decent to pretty bad, with no way of knowing what you will get when you order, just luck of the draw.
But how do you tell?Continue reading “Testing a Mirror”
The Last Lunar Eclipse for a While
Hope you had a chance to see this one… The next total lunar eclipse is not until March 14, 2025.
Confusion of Time
My body is awake.
At this point I know not to trust my sense of time or internal clock, I have traveled across far too many time zones. Entebbe to Portland required 27 hours of travel and crossed ten time zones. My body is simply not to be trusted.
The previous evening had consisted of little more than making it from the airport to my parent’s house, then directly to a long sought bed.
The clock reads nearly 7am.
How can this be? The time seems wrong and I have no confidence in the old LED alarm clock in the guest bedroom. Was it set properly? I fumble for the cell phone to double check the time. The phone confirms the seemingly inaccurate time.Continue reading “Confusion of Time”