275 replies to this topic

[De Lorme]

This is just Great! The best is Yet to Come! Highfnum do you think a 12nm Ha is the way to go and which manufacturer?
I'm so glad I bought the 8079HP. It's rejuvenated me looking up. I got so tired not quit seeing the glubulars.
And now being able to see nebulas also is icing on the cake!
De Lorme

[De Lorme]

Dxvid55, Have you had a chance to us the M&SG filter yet?
If so how much better{or worse}than your Celestron UHC/LPR
filter? Thanks for the info. I found a web site called
"Astronomical Filter Curves". It's been very helpful.
De Lorme

[Dxvid55]

No the clouds (but not the rain thank goodness) seem to be back for the foreseeable.

Did you mean this site,

http://www.astrosurf...ters/curves.htm

or something else?

[Dxvid55]

I finally got some decent shots thru this device
I wish to thank c7jhawk and De Lorme for heads up on this
one - I was raised that gen 1 was useless
not in this case!


http://www.cloudynig...6440546/page...

Those are great shots, Barnards Loop is very impressive. How does this intensifier compare with gen 3 you have used?

[highfnum]

very well better than G2
G3 has less distortion(flatter field) and less weight
g3 picks up a bit more of fainter stuff

g1 has brighter image and less noise but only zone 1 is good for astronomy zone 3 real bad
I think i got a way to design an eyepiece to get rid of most distortion -- future work

when you consider its 1/10 price of a used g3 very well indeed. Very funny a good 2 inch H-a filter will cost same or more that tube itself!

[Vondragonnoggin]

Those were impressive shots and showed off capability of cascade tube well. Does anyone know if there is a filter that concentrates on fairly narrowband H-Alpha AND narrowband SII in one filter? I haven't run across one yet, but do have a 35nm filter that works very good at much longer f ratios for bringing up existing light level, but still showing off HII regions.

[highfnum]

omega makes a filter 675 df20 that spans h-a sII
i only have the little 1.25 inch model
not well suited for this big beasty tube

I can try to see what it does once I mount on DOB

[Dxvid55]

"I think i got a way to design an eyepiece to get rid of most distortion -- future work"

That's interesting, what did you have in mind?

I've found that the high mag of 26mm plossl (only about 70-80% of intensifier screen fits in plossl fov) also magnifies the background noise "dots" which can be seen individually. Not a problem with bright objects, but the fainter the target the more difficult to distinguish the noise-dots from the target. The solution with faint objects is to use the lower mag of a loupe (all the intensifier screen only fills about 70% of the 5x loupe fov) so that background becomes uniform grey-green instead of individual dots.

So was thinking an ideal solution might be some sort of zoom eyepiece, then you could tailor the mag to brightness of each object, as each target is different.

The only zoom loupe I could find is this one,

http://www.bhphotovi...x_Zoom_Loupe...

which is expensive. Does anyone know any other zoom eyepiece which could be used for this purpose? (And if it flattens field distortion as well even better!)

I do have 3 different mags now (26 plossl plus a 10x and 5x loupe) which are probably enough for most situations, but a zoom would be more convenient and more flexible.

[highfnum]

idea: apheric lens design creates opposite pincushion
i got a shot at home ill post later


yes I use lower power loupes - noise not as obvious

[highfnum]

here is a g2 with apheric eyepiece
notice bend is opposite of p8079hp (see above)

Attached Thumbnails

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[cnoct]

Peak Optics makes some pretty good loupe's.

The 10x loupe (#1983) is really good and was at one time used by STANO Components on a number of their MX-9916 based night vision scopes.

I can't comment on their zoom loupe's but the 10x mentioned above is outstanding, for a loupe that is.

Here are a couple pictures of the ones I owned that use the Peak Loupe:

[De Lorme]

Cnoct, I just saw the video on YouTube you made showing how the TEC reduced the noise. Could I apply this to my 8079HP?
Would the Tec12706 work and if so what heat sink would go with it? Thanks for the help, De Lorme

[highfnum]

I was playing with iie
You can pump it up with momentary
off switch added to line

[darthtony]

Hi, i am thinking of buying the P8079HP tube for building a genral night vision scope(not specific to stargazing).Apart from here http://www.starlight...n1_p8079hp.html where else can i find it?Does it have reasonable quality for the price? Generaly what other optical equipmenty do i need?I have seen it used with CCTV lenses and SLR lenses, and jewllers loop eyepeices, what should i use(low price being the deciding factor)?What sort of specs do i look for and how do i calculate magnification etc?

[De Lorme]

DarthTony, If you go back a few pages you will find Highfnum and David's pictures which are great. There well worth the money and there not hard to put together.
What kind of telescope and mount would you be putting it on? De Lorme

[darthtony]

I just want to build a night vision scope, not for mounting it on a telescope, at the moment.

[highfnum]

Anchor ltd is second source also for p8079hp
link is somewhere in this thread early on

[Vondragonnoggin]

You can also look for Varo gen 1 cascade tubes. From $100 - $120 on eBay. The p8079hp tubes purchased by several around here have all been good though and price is close after shipping. If you are handy with PVC and fittings, you could build for quite inexpensive using the jewelers loupe mentioned previously for the eyepiece or even a PVS-2 weapons sight eyepiece. C-mount adapter for objectives offer all kinds of low cost lens solutions.

I have an ABS plastic housing scope for 25mm format tubes and they are sturdy. I use it hand held a lot. It has the c-mount adapter and I use a nifty fifty canon lens or a Pentax 200mm lens with it. It has a 1/4-20 bolt mount to attach to photo tripod if I want.

I imagine you could build similar with p8079hp tube for $200 and come out with a very nice handheld or photo tripod mountable scope.

This is the ABS housing for 25mm tubes with Canon 50mm lens on it. Yellow cap on jewelers loupe eyepiece protecting it from dust, but similar to jewelers loupe posted. That is a c-mount to Canon efs adapter used to attach the nifty fifty:

[darthtony]

Judging from the size, you are not using the p8079hp tube. How does it compare to Gen2 or Gen3 tubes?from what i have read, it has good sensitivity and SNR but somewhat significant distortion on the edges and it is huge. Can the sidtrortion be corrected opticaly.(eg coma corrector?)

[Vondragonnoggin]

That one isn't the p8079hp tube. Just showing an example housing where you could make a similar PVC housing for low cost.

I don't know of any correcters for the edge aberrations on the gen 1 cascade. Maybe some one else here does.

Size is shorter than gen 1 cascade, but it still is 25mm format. That one fits gen 2+ or gen 3 PVS-4 type tubes. Currently a gen 3 in there now.

[Dxvid55]

This is where I bought my tube,

http://www.anchorsup...generation.html

This forum has a lot of information about building a night vision version,

http://www.ar15.com/...t=359614&page=1

[Dxvid55]

I use 3 different mag lenses with my tube - a 26mm plossl, a 10x loupe and a 5x loupe - which are useful for different size astronomy targets. (In fact anything capable of magnifying a screen at short range should work.) But if I was building a hand-held spotting scope I would probably just buy the lens made for this tube, which you can get here,

http://www.ebay.com/...-Device-/141...

[darthtony]

What's the difference between the Varo IIT http://www.ebay.com/...er-PMT-Night... and the 8079HP tube?Are their performance similar?What about the distortion?

[Live_Steam_Mad]

The Varo MX 7854A/UV 25mm Generation 1, 3 stage Cascade tube seems to have a much lower gain (20 or 40,000) according to it's datasheet compared to the English Electric Valve Company's P8079HP Generation 1, 3 Stage Image Intensifier Tube (gain around 100,000). But they are hard to compare since the measurement units and measurement methods appear to differ.

The EE VC P8079HP is 55 GBP versus the Varo MX 7854A/UV at 64 GBP, at the moment.

Regards,

Alistair G.

[Dxvid55]

Last night I stumbled upon a very useful technique for looking at larger nebulae, which I haven't read about elsewhere so thought would mention it here in case anyone else wants to try it. I've always enjoyed binocular astronomy as well as scope viewing and use mostly 10x50 bins with a reclining deck-chair. Recently I read in an astronomy mag that it can help finding N Amer neb to hold up an LPR filter. So last night had a brainwave and dropped a baader neo LPR and UHC filters into x50 objectives, at first just to compare them by looking through one eye at each. But I found the dual view gave the best results. The brain seems to combine the brightness of the LPR with the contrast of the UHC. For the first time I was able to see the N Amer and also part of the E Pelican, as well as the E and N sections of the Veil and a faint hint around 52 Cygni. Result! Of course the filters were only in place by gravity and I did forget a couple of times, but as I was lying down they only fell on me not the floor! But it did occur to me this morning it would be very easy to secure them with some light masking tape and so be able to look at any angle. I wish I had thought of that last night when I was looking at Lagoon, Triffid, M22, M24, Omega, Eagle all of which, except Lagoon, were borderline visible due to low in S., summer twilight and light pollution. They will have to wait for next time. I only have the two 2" filters mentioned above, but I know several people here have much larger collections. It would be interesting to hear how well other combinations of filters work?

Back to main topic of this thread. If you could own only one hydrogen narrowband which would it be, for intensifier but also for visual viewing? In other words which would be the most versatile for both types of viewing and also for showing the most number of objects?
Thanks for any suggestions.