Help with 2.5x Powermate

Post by **Montana** » Wed Apr 15, 2020 9:37 am

Can anyone help. I have 2 massive bright reflection spots right in the middle of the field of view with this TeleVue powermate. I have tested it on everything I own now and it is unusable for anything.

This morning, amazing SSM results as predicted around 0.3-1.6, got the C11 out with CaK and as per Valery the 2.5x Powermate seems perfectly matched for scale and better contrast than all my others, but.. I have to put the main subject into the 4 corners of the frame to see it

not happy at all. What am I doing wrong with this powermate? why is it so different to the 5x Powermate and all the other Barlows I own? do you have to unscrew something to use it?

Alexandra

Post by **marktownley** » Wed Apr 15, 2020 9:49 am

Do a flat is all you can do short term. The seeing is better

Post by **Montana** » Wed Apr 15, 2020 10:20 am

Hmmm I have but it doesn't help not being able to see the target you are trying to focus on

surely this can't be right, I've never heard anyone complaining about this powermate before. I am scratching my head at the moment.

Alexandra

Post by **Montana** » Wed Apr 15, 2020 11:06 am

Some images

: flat.jpg (530.32 KiB) Viewed 6794 times

: Capture.jpg (500.86 KiB) Viewed 6794 times

Alexandra

krakatoa1883 · Post by **krakatoa1883** » Wed Apr 15, 2020 11:19 am

Hi Alexandra, same problem with my one and the 5x model too, the reason why I no longer use them for solar. The annoying reflection actually depends on how much back reflective are the filters placed in front of the Powermate, therefore with some setups they work while with others are unusable. Much better would be a very good 2 lens modular Barlow that can be set at different magnifications.

Post by **marktownley** » Wed Apr 15, 2020 11:26 am

Looks like the shadow of the cenral obstruction on a reflection of the main mirror, I bet if you measure then ratio of the secondary to the primary it will be the same in the spot in the image.

I did a barlow experiment the other week. For hi-res CaK this one was a clear winner by far https://www.telescopehouse.com/barlows/ ... rlows.html - it's on sale too, quick, treat yourself before it goes!

Post by **Montana** » Wed Apr 15, 2020 11:32 am

Thing is, it does the same even on the TEC and Solarscope too. It is useless on everything, so how do they sell it?

Alexandra

pedro · Post by **pedro** » Wed Apr 15, 2020 11:38 am

Try using a filter in front of the 1 1/4" adapter. Since I've been using filters (H-alpha 35nm/7nm or Ca-K) these reflections less evident or absent (refractors)

Post by **Montana** » Wed Apr 15, 2020 1:52 pm

TeleVue are closed and don't seem to have an e-mail address which is weird

I think it maybe something to do with the spacing between the camera and the lens https://www.cloudynights.com/topic/4068 ... ate/page-2

Alexandra

JochenM · Post by **JochenM** » Wed Apr 15, 2020 2:02 pm

I own the same PowerMate. I've had a somewhat similar thing happen when I use it on my 150mm refractor (be it much less serious than what you're seeing).

I thought it was just a reflection between the camera and the lens; added a tilting adapter in front of the the camera and that eliminated the problem.

Carbon60 · Post by **Carbon60** » Wed Apr 15, 2020 9:19 pm

Hi Alexandra, I see the same on the RCT with my 2.5x PowerMate. Tilting the camera helps, and flats. There’s probably something that could be done with a circular polarising filter to control errant reflections but that needs some experimentation.

Stu.

Post by **Merlin66** » Wed Apr 15, 2020 11:18 pm

Alexandra,
I use the x2.5 PM most of the time with my ED80 and either the ASI 174 or ASI 1600 for white light, CaK and Ha.
I do use the T thread adaptor and a T2 tilter. The only real issue I have is the NR.

: 100_3362.JPG (87.67 KiB) Viewed 6730 times

Post by **Montana** » Thu Apr 16, 2020 7:41 am

Thanks guys for all the suggestions, I'll try them all after I hear back from TeleVue. Apollo kindly supplied me with their e-mail address, so let's hope they reply to me. One thing I have learned is that you shouldn't have to tweak, twiddle and compromise on performance, it was expensive so it should work and I am not a happy customer. We will see what they say, I think some of the lenses aren't tilted enough like Bob Yoesle indicates in the CN thread. It doesn't work on any of my telescopes so at the moment it is useless.

Alexandra

Carbon60 · Post by **Carbon60** » Thu Apr 16, 2020 6:26 pm

Hi Alexandra,

This is the bright spot I see with my 2.5x Powermate on my RCT (ignore the darker patches which are something else I need to deal with).

: Bright spot.jpg (76.13 KiB) Viewed 6686 times

I eliminate this by tilting the camera.

Stu.

DeepSolar64 · Post by **DeepSolar64** » Thu Apr 16, 2020 8:16 pm

Does a conventional barlow do this? Like a Celestron or Meade 2x model?

Post by **Montana** » Fri Apr 17, 2020 7:23 am

Come on guys! if you all have a bad reflection in this product why are you settling for bodges to get round it? If I bought a telescope and every time I looked through it I had a bad bright spot in the middle so I couldn't see the Moon I would send it back not fit for purpose. I wouldn't sit there and think oh well it doesn't matter, if I just tilt my head a bit the bright spot goes to one side or tilt the camera it goes away a bit. It is faulty and should not be sold. If everyone complained they might fix it. As Stuart's bright spot is lower than mine it indicates that there is a variable in the construction so the bright spot moves, therefore I bet some have no reflection at all. Therefore I presume there is not enough tilt in one of the lenses in the train. I have no bright spot in 5x Powermate.

I have never encountered this even with my ultra cheap and far superior barlows from other brands. Currently I wouldn't pay £1 for this Powermate in its current condition let alone the price it sells for.

If I had settled on my Lunt CaK module being so so, then I wouldn't have used it because I never got any good results from it, then I wouldn't have the amazing replacement Lunt CaK module which gives me so much pleasure now. These things are too expensive to settle for bad products.

If I am doing something wrong then I will apologise for my rant because I know I do sometimes miss the point

Alexandra

Post by **marktownley** » Fri Apr 17, 2020 7:30 am

Sold my 2.5x powermate many years ago for exactly this reason way back in 2013... Have you tried your 3x TV barlow in CaK?

Carbon60 · Post by **Carbon60** » Fri Apr 17, 2020 7:53 am

I agree with what you’re saying, Alexandra. It shouldn’t happen with an expensive item such as this. Tilting solves the immediate issue, but it isn’t a fix. I’ll be interested to hear what the manufacturer has to say.

Stu.

Post by **Montana** » Fri Apr 17, 2020 10:58 am

Yes Mark, it is absolutely fine but the contrast isn't half as good as the faulty 2.5x Powermate. I haven't heard anything back yet from TeleVue but it does say they are closed till further notice. I guess they are at home staring at the wall rather than answering customer questions via email. Maybe they don't know how to remote work?

Alexandra

yltansg · Post by **yltansg** » Fri Apr 17, 2020 11:41 am

Dear Alexandra,

I had the same problem with my Televue barlow. I switched to another barlow and the problem went away. This is my setup for CAK imaging:

I am pleased that the Lunt CAK-K modules are able to produce fairly good images, such as this (limited by my post-processing skills):

So keep the lunt CAK-K module and get another barlow.

Alfred

Post by **Montana** » Fri Apr 17, 2020 11:43 am

What Barlow do you have?

Alexandra

yltansg · Post by **yltansg** » Fri Apr 17, 2020 12:06 pm

Montana wrote: ↑Fri Apr 17, 2020 11:43 am What Barlow do you have?

Alexandra

Hi Alexandra,

I use two types of barlows - (1) Orion Shorty 1.25-Inch 2x Barlow Lens and NPZ barlow (http://www.npzoptics.com/catalog/access ... nzy_barlou).

They are both good.

Alfred

Post by **marktownley** » Fri Apr 17, 2020 12:09 pm

Montana wrote: ↑Fri Apr 17, 2020 10:58 am Yes Mark, it is absolutely fine but the contrast isn't half as good as the faulty 2.5x Powermate.

Interesting to know about the contrast and the 3x TV, I had one on my 'wish list' for a while now, but based on this I think I will scrub it and put something else on instead

Post by **Montana** » Fri Apr 17, 2020 2:12 pm

Mark, the 3x Barlow TV is fabulous in WL and Halpha and in CaK on the TEC140. It was just less contrast in CaK on the C11 compared to the 2.5x Powermate. It is a cracking Barlow and I wouldn't part with it

Alexandra

Post by **Montana** » Fri Apr 17, 2020 5:06 pm

Just had a e-mail from TeleVue, due to New York City advice they are not allowed to answer emails until the 15th May. What, you might catch the virus via email?

I guess they haven't learned to work from home like the rest of us then

Alexandra

Post by **marktownley** » Sat Apr 18, 2020 7:24 am

Montana wrote: ↑Fri Apr 17, 2020 5:06 pm Just had a e-mail from TeleVue, due to New York City advice they are not allowed to answer emails until the 15th May. What, you might catch the virus via email?

I guess they haven't learned to work from home like the rest of us then

Alexandra

Honestly not sure what they will tell you that will help tbh. Fairly certain when the powermate was designed they didn't have CaK filters in mind. I sold all my TV stuff years ago, the only thing I have of theirs now is a 15mm plossl which is nice for viewing in Ha, before that I had ethos, radians, naglers, panoptics etc, must of had thousands of pounds worth. They were great for night time stuff, but that's not my boat, and I found that much cheaper stuff is much better for solar - optically simpler designed and fewer glass elements which is CaK is very important for higher transmission and shorter exposures.

Post by **Montana** » Sat Apr 18, 2020 3:37 pm

Mmmm I wonder too. Thing is I couldn't now sell it second hand as my conscience wouldn't allow it. If is bad on the TEC140 in WL then I guess it is bad on the Moon also?

Anyway, I have bought your recommended 3x Barlow, let's see how it goes head to head with the TeleVue 3x Barlow

Alexandra

Post by **marktownley** » Sat Apr 18, 2020 4:09 pm

Aww, you could sell it, because most people wouldn't use it for solar like we do...

I feel the pressure is on with the barlow comparison, look forward to the findings

MapleRidge · Post by **MapleRidge** » Sat Apr 18, 2020 11:44 pm

Alexandra and all...

I'm late coming to this topic, but I too have the same bright spot in my CaK images using the original B1800CaK and the modified version using a solar wedge to allow it to be used up to 6" scopes. Interesting to hear the tilt device might reduce it...always have only used it in Ha.

Flats reduce it greatly, but it still stays in the image...always frustrating.

Brian

DeepSolar64 · Post by **DeepSolar64** » Sun Apr 19, 2020 12:12 am

marktownley wrote: ↑Sat Apr 18, 2020 7:24 am
Montana wrote: ↑Fri Apr 17, 2020 5:06 pm Just had a e-mail from TeleVue, due to New York City advice they are not allowed to answer emails until the 15th May. What, you might catch the virus via email?

I guess they haven't learned to work from home like the rest of us then

Alexandra
Honestly not sure what they will tell you that will help tbh. Fairly certain when the powermate was designed they didn't have CaK filters in mind. I sold all my TV stuff years ago, the only thing I have of theirs now is a 15mm plossl which is nice for viewing in Ha, before that I had ethos, radians, naglers, panoptics etc, must of had thousands of pounds worth. They were great for night time stuff, but that's not my boat, and I found that much cheaper stuff is much better for solar - optically simpler designed and fewer glass elements which is CaK is very important for higher transmission and shorter exposures.

I never have been able to afford TeleVue. They are so pricey. I have only one TV eyepiece. A 20mm Plossl. I use it for white light solar. Most of my nighttime eyepieces are Explore Scientific though I do have a good Orion 16mm extra wide field eyepiece and an old 28mm Edmund RKE which I use very often. Most of my solar eyepieces are Lunt and Coronado. I have two Meade barlows and a Celestron barlow.

Mark, at least your expenses now doesn't have to be divided between nighttime and daytime astronomy. And with solar light pollution is NEVER a problem!!

Post by **Merlin66** » Sun Apr 19, 2020 1:04 am

Alexandra,
Looking at the CN link you gave....
Using the T thread adaptor seems to have solved the users "reflection" issue....
I don't know what else to suggest... I don't see your central "hot spot" on my flats or images.....
EDIT: What do flats look like with the PM and no other filters etc. just the objective cover by plastic and bright sky? Might help determine what is focusing the bright spot?

Post by **Montana** » Mon Apr 27, 2020 7:07 am

OK so at last week I did some imaging with the C11 and had Baader WL solar film on, so this is straight through with the 2.5x Powermate and the ASI174 camera, so no reflective surfaces etc. It's quite interesting, do you think my collimation for the C11 is good enough? I could use this and sell it for a mint as a SCT collimation tool

it beats having to go out at night to find a star

: flat 2-5x WL.jpg (633.1 KiB) Viewed 5089 times

I then tried on Saturday with the TEC 140 with the CaK wedge (as I bought it for CaK) and this is what I saw

: Flat CaK 2-5x.jpg (467.72 KiB) Viewed 5089 times

With the Baader Herschel wedge it was barely noticeable as was the Solarscope, but still brighter centre but doesn't really affect imaging in any way.

Alexandra

Post by **marktownley** » Mon Apr 27, 2020 7:18 am

Would be great as a collimation tool for the c11, great view of the secondary mirror. Looks like with the TEC you are seeing the reflection of the 2 ERFs that sit in the nosepiece of the CaK module - that's why they're sat offset, the lens elements if the TEC certainly aren't misaligned.

alessbonsai · Post by **alessbonsai** » Sun May 19, 2024 8:38 am

identical defect, very evident on the moon and a WL, almost non-existent in Ha. how did you solve the problem?

Post by **Montana** » Sun May 19, 2024 11:32 am

I did solve the problem, you have to sit the camera at least 4cm away from the Powermate. I used a 4cm extension tube.

Alexandra

pedro · Post by **pedro** » Sun May 19, 2024 12:49 pm

I had the same problem with my X2.5 Powermate and a flat corrects the reflections. It helps to use an extension tube

alessbonsai · Post by **alessbonsai** » Thu Jun 06, 2024 9:52 am

It seems that I only solved the problem by moving the camera away from the barlow
thanks for the advices

Alto · Post by **Alto** » Wed Sep 04, 2024 12:31 pm

Montana wrote: ↑Sun May 19, 2024 11:32 am I did solve the problem, you have to sit the camera at least 4cm away from the Powermate. I used a 4cm extension tube.

Alexandra

Interesting solution. I have a similar glare on my Daystar Ha Quark Chromo - it's not quite the same, it's central but out of focus and really annoying when trying to bring out proms. Doesn't show, though, mid disc.

Worth a gamble, nothing else seems to work.

astrovale · Post by **astrovale** » Wed Sep 04, 2024 5:10 pm

Late to the topic and glad you solved your problem Alexandra. However, I use 3 powemates, 2.5, 4 and 5. But I use them only for calcium and wl as for h-alpha I use baader telecentric or ffc.

I never noticed this problem in the 5x and 4x and only very, very faint in the 2.5x {usually solved without issues by the ff). I only use a refractor, so the problem cannot be linked to the reflector design.

Very strange though. Powermates have been in my arsenal forever now. I love the 2" 4x on my wl wedge

Luca

cybermayberry · Post by **cybermayberry** » Thu Sep 05, 2024 12:07 am

Montana wrote: ↑Mon Apr 27, 2020 7:07 am OK so at last week I did some imaging with the C11 and had Baader WL solar film on, so this is straight through with the 2.5x Powermate and the ASI174 camera, so no reflective surfaces etc. It's quite interesting, do you think my collimation for the C11 is good enough? I could use this and sell it for a mint as a SCT collimation tool it beats having to go out at night to find a star

flat 2-5x WL.jpg

I then tried on Saturday with the TEC 140 with the CaK wedge (as I bought it for CaK) and this is what I saw

Flat CaK 2-5x.jpg

With the Baader Herschel wedge it was barely noticeable as was the Solarscope, but still brighter centre but doesn't really affect imaging in any way.

Alexandra

At least you look collimated.
I have a powermate 2.5x and do not have that issue in my sample. I have not had any issues using my sample with a SCT or refractors.