I was noting the proximity of Pluto (The Maligned) to Venus today. You'd need something the size of the HST to separate Pluto out of all the light from Venus though.

Dave

 

Or a 6000x Barlow lol.

 

To be honest Ray, the ST80 punches above its weight for planetary. I really want to see Saturn with it. I've tried the UHC-S with a 16mm T5 Nagler for 25x with a 3.2mm exit pupil. The conditions weren't brilliant but I just about got away with it. The UHC-S was threaded into the eyepiece with the Semi-Apo in the diagonal. I reckon I could have taken the Semi-Apo out as there's no point stacking the two. Unfortunately it was first light with the ST80 and I was so excited I forgot to take it off the diagonal lol.


I've ordered an 0.5x Antares Reducer as it cuts the f/l by 40% raising the focal ratio to about f/3 on the ST80. Although I'm not sure what this will do to the refractive index. It can give the scope/eyepiece a wider FOV. I think when I look for nebulae with the ST80 I'll start off without the reducer and with the 19mm Panoptic for around 21x and a 3.8 mm exit pupil. Depending on the target's brightness and overall conditions it may be possible to take the UHC-S to around a 2mm exit pupil.

 

Thought I'd share this ...

 

That .5X Reducer has my eyes open. I'll have to do some tracking on it for reviews, attempts, problems, etc. Antares comes along with interesting surprises more-often-than-not, in my experiences.

Below is a link to a very good article. Though written around MallinCam video-cams, the principles it shows remains the same regardless the peripheral-gadgets. Here be:

http://www.mallincam.net/uploads/2/6/9/1/26913006/focal_reduction_for_dummies.pdf

I've copied the YouTube-link to your Moon Hoax goodie. I need a good laugh today. I just had to fire one of my doctors, and mirth is prescribed by me for me!

> ( )*< Kwak! Kwak

Dave

 

I know Antares, Meade and Celestron make a reducer specifically for big SCT's. The bloke who wrote the book on Messiers I bought states that he used an Antares. I think it will bring the ST80 down to 240mm f/l and the Skymax down to 780mm f/l. TS Optics also do a 0.5 reducer.

Cheers for the PDF.

The chap in the YouTube link knows his film studies!

 

I've got a Meade FR 6.3 and the now-rare 3.3. Meade discontinued the 3.3 because of tons of complaints from people who tried them, visually, and found they didn't work. Rather than tell these people they won't work 'visually,' Meade stopped making them! Meade often shows a failure-to-think disorder. For video and photo-work, the 3.3 were excellent! I was lucky to grab one in the brief window of availability.

MallinCam more recently made & makes excellent ones as well:

http://www.mallincam.net/optical-accessories.html

They, of course, aren't limited to working only with MallinCam products, though Meade might wish to think so!

I'll have to take a look at this Antares .5X one also. You've intrigued me, you rat!

See you around the Poor-House,

Dave

 

By the by, I don't know what it's truly going to cost you, but...

http://agenaastro.com/antares-1-25-0-5x-focal-reducer.html

Hope you've found similar - or less? Please to keep informed. Thanks!

FR & Filter -

Dave

 

Yes, that's it. Although I ordered it locally as it can take some time for stuff to get to me from Agena. I should receive it Monday.

TSO do one, they're probably made in the same factory.

http://www.teleskop-express.de/shop...l-reducer-0-5x---1-25-inch-filter-thread.html

Just a few thoughts and calculations ...

I calculate that Phillip Pugh’s 127mm Skymax, the scope he viewed most of the Messier Objects in his book with, was reduced from a 1500mm f/l to 900mm if the Antares reducer shortens the f/l by 40%.

1500 - 600 = 900

900mm is the same f/l as the ‘Bazooka’ (my 130mm Explorer). Both have an f/number of about 7 (the Bazooka’s is actually f/6.9).

Pugh claims that the eyepiece he used mostly was a 32mm (Sky-Watcher) Plossl. A 32mm eyepiece gives 28x (approx) for a 4.5mm exit pupil on a 5“ (or thereabouts) scope.

This sounds like a decent optimal magnification/exit pupil for some of the more difficult MO’s.

Both Sky-Watcher and Celestron claim that their Plossls work best at f/6 or above.

A 102mm Skymax like mine combined with an 0.5/40% reducer should have a 780mm focal length.

1300 - 520 = 780

This brings the 102mm Skymax to f/7.6. A 32mm Plossl will give 24.3x for a 4.2mm exit pupil (although I have a 30mm Vixen NPL which will give 26x for 3.9mm exit pupil).

However, he also claims that some of the MO’s weren’t so easy for him, particularly M20 and he would use the ST80 for some of the difficult MO’s. The Trifid is pretty easy for me and I thought it looked good this year with the Bazooka at 64x for a 2mm exit pupil (14mm Baader Morpheus plus Baader UHC-S). Although it’s probably my location on the edge of the greenbelt and high altitude above sea level.

Using the ST80 with the reducer brings it down to a 240mm focal length for f/3!

400 - 160 = 240

Pugh says that he’d use this combination with a Sky-Watcher 32mm Plossl as well. Which gives 7.5x for a massive 10.6mm exit pupil. I suppose any vignetting or EOF distortion wouldn’t matter so much on faint fuzzies. Although I’d expect some CA as well. Probably have to get the Baader Contrast Booster out lol.

Without the reducer on the ST80 a 15mm eyepiece will give 26.6x for a 3mm exit pupil. With the reducer my 11mm TeleVue Plossl will give 21.8x for a 3.6mm exit pupil. Which may just work.

I think I’ve worn my calculator out lol.

 

I got the idea from Phillip Pugh's book but I think he mostly used it on his 127mm Skymax. Mak's have notoriously narrow FOV's and are usually slower than f/10. Great for planetary but a bit pants for DSO's which require fast f/numbers and larger FOV's.

I thought it might be OK on my 102mm Skymax. With the Vixen mount I could range from azimuth to zenith fairly easily. It doesn't make it that fast though, but it would probably seriously improve some DSO viewing, and with no CA. Dewing would still be a problem though. My Skymax has no built-in dew sleeve like your Meade and the ST80.

I'm a tad ambivalent about using the reducer on the ST80. Most eyepieces I have for it probably won't fare that well on an f/5 scope let alone reduced to f/3. The faster the scope, the pricier the glass! Luckily I have some expensive small bodied EP's that should do well (Antares 15mm Masuyama clone, 10mm Baader Eudiascopic, orthoscopics, TV Plossls etc).

Although, the wider FOV may be helpful for finding faint objects. I have a 20mm TV Plossl that would yield 12x for a 6.7 mm (approx) exit pupil with the reducer.

What was the size of that Vixen EP you bought Ray? It might benefit from a reducer.

 

OK. 150x on the Meade is a nice base planetary magnification. Also, you could make that 240x on the Meade by threading a Barlow element directly onto the draw tube. Giving you two good lunar/planetary magnifications. Although 240x may be better just for the Moon.

The reducer should diminish the 600 f/l of the Meade to 360mm. Dropping the magnification to 90x. With a Barlow element and a reducer you can get a selection of 90x, 150x and 240x all out of the one 4mm Vixen.

Using the same method, the 4mm Vixen should give you 60x, 100x and 160x on the ST80. This gives you much more flexibility. The Vixen is good quality and should deal with the faster f/number (f/3) when the ST80 is used with the reducer. It will give a 1.3 mm exit pupil for 60x. This could be a decent high DSO magnification for some targets.

The Big 25 would give a low 9.6x for an 8.3mm exit pupil on the ST80 with the reducer. If I'm right of course lol. This is all theory for me at the moment. I'll have to keep you informed after some testing in the field. According to his book Phillip Pugh had to resort to 7.5x on the ST80 (with reducer) with a 32mm Plossl to see some faint objects. Although I've read that there can be vignetting problems with EP's over 25mm with a reducer. It may not be important with very faint objects though. He looked at all of the MO's visible from the UK and some were 'see once and cross them off the list' more or less. I'm not sure where he was observing from though and he seemed to be plagued by extinction with some of the low southern objects (like M4). This doesn't affect me so much and M4 can be well visible to me depending on conditions. He had some problems with M20 as well, which also isn't a problem for me and I thought the Trifid looked good this summer even with the Baader UHC-S.

When the weather gets more unpants I'll have to test the reducer and I'll tell you what I find. At the end of the day, the reducer is basically an anti-Barlow lol.

 

We have a problem, Houston...

I've been reading around the net on the Antares 1.25" 0.5X F-R. Many preople have brought up the issue they've all had with these: The threads are cut way too small so it will not thread into the barrels of EP's and camera-snouts. Instead it just slides! And they all suggest about 5-wraps of Teflon® tape around these as being the best fix. So put Teflon® tape on your shopping -list. Hardware stores with plumbing-sections is a good bet (so thinketh my tool-head).

They also offer the Antares 0.5X in a 2" format, but I've found no reference to these having any problems. Jim Henson, the proprietor of ScopeStuff.com offers these in 2" only - which tells me something right-off. Jim's a great guy! - and his price on the 2" 0.5X Antares is only $28.00/ea. A boxcar on a freight-train full of these must have crashed onto his lawn!

As to your query, Ray, here's one way to understand what it does:



As to what will these do for small, fast refractors? I do believe that's what is being found out right about now! I'll be looking foreward to what Mak has to say - after the soon-to-materialize typhoon has withdrawn from the UK.....

And Ray, do read through the "Focal Reduction for Dummies" I dropped in here a bit ago. Download yourself a copy. The real trick to factor in with these little glassy things is the spacing of them from lens-to-eye to lightpath, etc. So be prepared with an assortment of spacers to find the best ones possible. Focal-Reducers come in many strengths such as 0.8X, o.5X, 0.63X, 0.33X, so forth. With the spacers thrown in, you can take 'em down to ulttra-fast 'speeds' like F/2.4!

Expect some interesting problems along the way. Like accidently inventing the "Phaser" and disintegrating your town...

Ah well - off to practice my "It was an accident, Your Honor!"

Dave

 

Hmmm ... that's disconcerting Dave. I suppose I'll find out tomorrow. I knew I should have bought the TS Optics version. After some research it seems the GSO equivalent can suffer the same thing. Hopefully these were just bad production batches. As long as it fits my diagonal I should be OK.

 

I read this in the reviews in AgenaAstro, go figure! I hope your right - one bad batch.

On another note: A new member joined SGL. He'd been rapidly banned in CloudyNights, and was a new member.So I went there to check on a few older threads I am following. I clicked on two links - including a review of the VITE 2X Barlow. But instead:

I was hijacked to a XXX-Porn site! Which I couldn't close out of - used Malwarebytes later and found/killed - and at another link in CN - same thing!

I'd suggest avoiding CN for awhile. They need to do a day-long sweep of their entire site.

'Ta,

Dave

 

Thanks for the head's up on both things Dave. Jeez, it's a jungle out there lol. I run Malwarebytes Anti-Exploit now as well. The freeware version shields a lot of browsers by default including Maxthon. I'm very careful about clicking links, I often scan them with VirusTotal first. You don't expect it on an astro forum though.

I'll see with the Antares tomorrow I reckon. Hopefully it was just a dodgy batch. The optical quality of the Antares is supposedly good though, so I hope it fits.

 

Had an open window session on a daylight/twilight Moon for a while (90mm Mak). At 52.6x, 66.6x and 83.3x. Early on I was surprised how good the #21 Orange filter was for contrast. Later as it got darker I tried the 80A Blue and the #15 Yellow filters.



The #15 wasn’t so good in the daylight but as it got darker it revealed more contrast detail than either the #21 or 80A. Transparency wasn’t brilliant but Theophilus was outstanding dramatically shadowed by the terminator.



I actually didn’t recognise it at first. Seeing the Martian phase was more difficult but Venus was comparatively easy. I’m guessing the wispy cloud and the Wratten #15 had a lot to do with this.

Images CDC & VMA

 

Indeed - you don't expect that in astro-groups. And worse yet: The link to the review of the VITE 2X was on their home-page!

What a bunch of twits! Too busy throwin' out dem 'ferigners!' Instead of maintaining defense software.

Where'd I leave my Haz-Mat Suit...?

Dave