Hi Dave,

Yes, I did, and I'm amazed, too. Back in 2012 I was observing during evening twilight with my old XT-6 using a Wratten #80-A and a Zhumell UHC filter stacked. I was able to observe cloud detail, as shown in the attached sketch I made.



I have a Wratten #47 that does a good job on Venus. After reading Reggie's post I took out my TV-85 and had it set up and almost ready to image when.....I had to bring everything back into the house in a hurry! The recommendation for 8" and larger scopes has more to do with visual, but it's not etched in stone, as my sketch shows. Imaging Venus with small apertures is no different than imaging faint fuzzies with little refractors. It's a simple matter of taking longer exposures.

An IR pass filter can be used to cut through less than ideal seeing, which seems to be the norm here. It can also increase the contrast of Martian albedo features, one of my main interests at the moment. IR pass filters can also sharpen lunar detail and enhance contrast, and it can bring out interesting details on Jove. On Venus it can have the effect of cutting through the glare. Similar to the effects of using blue filters on Mars to observe polar ice and clouds, and green filters to observe ground fog and differentiate it from clouds, IR and UV pass filters can be used on Venus to observe cloud cover at different depths.

I'm also interested in imaging nebulae with an IR pass to see what I can capture. I imaged the Orion Nebula (who hasn't?) and found I could capture way more of the nebula when passing IR. Should be interesting on the Lagoon, etc.

I know an RGB camera is not going to image in IR as well as a mono camera, even if set to capture mono, but I have seen some really nice results posted on various websites. Has to do with the Bayer Matrix. I do have in the back of my mind getting a mono camera with larger sensor sometime in the future, so...

Ed D

 

BTW, I wanted to share with everyone the current sale price of the Optolong IR pass filter at Agena. They are good filters, but I believe there are only two left in stock now. This, just in case anyone has been looking for one, but didn't want to shell out nearly $100 or more.

The Venus/UV pass filters are also on sale at a great price for what they are, but still out of my budget. I also don't see anywhere near the utility of an UV pass filter as I do an IR pass filter.

Ed D

 

Agena Astro rocks!!! Four business days and the filters are here. In all the years I have been doing business with Agena they have always been great in every respect. THANK YOU!!!

So, here is what they look like in their cases:



On the left is the Optolong 685nm, and on the right the ZWO 850nm. Very nicely packaged. The Optolong 685nm has a coating that reflects a teal color. But, when I look through it, bright lights appear a very deep red. I can't see anything other than the light through the filter. The green lettering is a reflection of my phone.



The ZWO 850nm is another story. It looks more like a black cap for the camera, and by that I mean it is solid black like a piece of plastic. I held it up to the lights and I couldn't see anything. I'm sure light is coming through the filter, just not at a frequency I can see. Nothing, nada, zip.



Venus was up high in the sky and the clouds were nowhere near. I took out the CG-4 GEM and set up my AT72ED just to play with it. I centered Venus in the eyepiece, then swapped it for the camera. Once I had Venus centered in the screen and focused I installed the 685nm filter. I had to up the capture time to 7 seconds per frame, but it was looking good.

At this time, start thinking of the oldies song RAINDROPS KEEP FALLING ON MY HEAD.

Stay tuned. I'll get some images sooner or later.

Ed D

 

As Gomer Pyle USMC used to say: "SURPRISE, SURPRISE, SURPRISE"

Conditions were bad last night, lots of haze and heavy moisture mucking things up, which is where the IR pass filters shine. However, the surprise was that my best results were obtained with the TV-85 and ZWO 850nm filter. With a small aperture and such a dark filter I thought that combination would have been the wash. I also imaged with the 685nm and Wratten #47 Violet filters, but results were questionable.

I need a good night so I can set up my 6" Mak and try the filters. I also need to learn how to combine images, similar to LRGB processing, so I can combine the results of the different filters into one image. Even though the 685nm and #47 filter results were questionable I could see different cloud layers/structure on Venus. Stay tuned.

Ed D

 

I also want to mention that last night, while I was playing with the gain settings, I noticed that as I lowered the gain to where the planet was becoming dim on the computer screen, I cloud tell that I was capturing some detail. This is very similar to Reggie's great results using a polarizing filter to kill the glare.

Ed D

 

At this point I have used my IR Pass filters enough to report some initial impressions.

Both filters have worked and given results in the smaller TV-85. However, in the 85mm aperture the frame rate is slow. In the 6" Mak the frame rate is pretty fast because of the much greater light gathering of the aperture. The 685nm filter works great and with good frame rates, even in smaller apertures.

I'm really liking the 850nm filter. I thought it would be too much, too far into the IR range, but the results I'm getting are nice. Don't get me wrong, I like the 685nm filter, too. But the 850nm filter produces some really good high contrast images. For $24 shipped to my door from Agena it's a steal of a deal. I'm really glad I got it. I still have to do a little more with the 685nm filter.

@REGGIE: For the princely sum of $24 I think you could do some really nice work with an 850nm IR Pass filter and your 5" Mak. Good targets I can think of are Jupiter, Venus, Mars, and Luna.

Ed D

 

At this point in time I have two Optolong filters; an UV/IR Block, and a 685nm IR Pass. The threads on the Optolong filters are cut a little larger diameter than my other filters. I have had problems threading the Optolongs into some of my accessories. I have resolved the thread fit issues, but it's a PITA, especially with new equipment, that someone else may not be equipped to carry out. On the flip side, the optical quality of these filters is super, on par with the quality name brands.

Ed D