Today's Image of AR2665 and AR2666 from Muskegon, MI

This is a quick image snapped between clouds with the 90mm MAK and DS 2.3+:

AR2665 from Lake Michigan -- 7/13/2017

AR2665 is decaying, but it is still an impressive sight in white light. A new active area, AR2666, is visible above and to the left of it at the top of the frame; it looks like a few small black specks. This is a stacked image (250 AVI frames) taken with a 90mm MAK and Mallincam DS 2.3+. Stacking and wavelets in Registax.

AR2665 with 90mm MAK & H-Alpha

AR2665 is the biggest sunspot of 2017, stretching over 125,000 km across the solar surface.  This image was taken on July 8, 2017, and, like all images, was captured with the superb Mallincam DS2.3+ imager:

Here is a crop:

The sunspot is a complex of many cores, capable of producing M-Class flares.

The H-Alpha image shows a little more of the underlying structure:

And here is the crop; it's interesting to compare it to the white light image:

There was also a nice "hedgerow" prominence visible on H-alpha:

I took another image on July 9, but for some reason, it does not show as much detail. This was a hurried shot, and I suspect the imager was not orthogonal to the optical axis of the scope.

Weather permitting, I'll try to follow this spot over the next few days.

ETX 90 OTA Test 7/1/17

Despite very poor seeing, I decided to put the 90 OTA through its paces. The results are not bad--I'd like to try in better seeing.  Here is the moon, taken with the 90, a EQ Pro mount, a Mallincam DS 2.3+ camera and a 2x Barlow:

Although it was like looking through choppy water, this image still has some fairly good detail. Jupiter, however, was a different story:

Here's a crop:

Not much detail is visible, but stars directly overhead were scintillating wildly and the planet was caught in thermals above a neighbor's roof. I'm hoping to try again next week in Michigan where I may be able to image through laminar airflow off the lake.

"Deforking" an ETX

I had a couple of emails asking how to defork an ETX telescope.

The ETX 90 and ETX 125 were optically superb scopes, but the mounts left a lot to be desired, especially the early models. I deforked my 125 a while back and it works very well on both my EQPro and ZEQ 25 mounts (although I am much more comfortable with it on the ZEQ!). My old 90 model (a 1995-vintage non-goto scope--I think Meade referred to this model as the  ETX 90 RA) worked pretty well on 3 AA batteries. Tracking was decent enough for visual work and for imaging bright, solar system objects. The other day, I dusted it off for some solar imaging and found that (most likely) the circuit board had died. I decided to defork the OTA so I could use it with the iOptron mounts.

As I've already deforked it, I can't provide pix of the process, but I can answer the question both asked: where are the screws you need to remove to release the OTA?  Here's the pic you need:

In the above image, the OTA would be vertical and the screws you need to remove fit in the four holes you can clearly see in this image. You'll need an Allen wrench (not sure what size, I just have one that fits!). After you have removed them all, simply pull the OTA forwards to remove it; it should slide out pretty easily.

I mounted my OTA on a dovetail. As the dovetail was not designed for the ETX 90 OTA, I drilled a couple of extra holes into it. The holes should align with the brass, threaded screw "sleeves" in the oblong block at the back of the OTA. 

Here's a pic:

All-in-all, it was a 10-minute job and the 90 is now usable again (see my last blog entry with the solar image).

Eclipse prep 2

Yesterday, I deforked the ETX90 OTA. I found an old dovetail and adapted it by drilling a couple of new holes in it (the existing holes were about a tenth of an inch too close together for the ETX--Murphy's Law, I guess). I mounted it on the EQ Pro and took a few images--including that below:

The Sun on June 29, 2017. AR 2664 is visible above and to the left of center

I was surprised by the image scale, compared to the ST-80--although an 80mm f/4 scope will obviously give a much bigger FOV than a 90mm f/13.8 scope. It's nice to have the 90 back in use again (I'll try some lunar and planetary images later), but the choice for eclipse scope is pretty clear: the ST-80 will provide a much better platform to image the corona.

Eclipse Prep

I plan on traveling to Nashville, TN for the solar eclipse on August 21. My plan is to take white light images with my SLRs, plus scope and solar filter. Unfortunately, the white light scope I usually use for solar work, an old 1995-vintage ETX 90, has stopped tracking. Although it worked a few weeks ago, it refuses to track now, even with fresh batteries. I think I'll probably take it off the base and add a dovetail, eventually.

The saving grace is that the filter pretty much fits my ST-80, and the 80 has a wider FOV than the ETX, which should enable some nice corona captures when I whip off the filter at totality. Today was a test of the EQPro, ST-80 and Mallincam DS16C combo, and it worked very well. The FOV is wide and the detail captured is very satisfying. Here are a couple of shots, with AR 2664 is just visible as a dot above and to the right of center in these images. I enhanced the images with an unsharp mask to bring out the "orange peel" texture. I've included an unprocessed image to show how well this combo captures this detail. The first two images, below, are processed, the last is not.