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Fozzie

It's not often I get over 200x... tonight though...

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And the batteries have left the building... power out on the mount... still at least my bum is warm.

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33 minutes ago, Knighty2112 said:

Clouds rolling in now, so called it a night. Feet are blooming frozen, but well worth it. The moon was as clear as a bell tonight, with increadible seeing. Pushed it up to 220x with a 4.5mm EP, but too much light scatter with it, so used my 6mm WO EP instead for a clearer view. Best I’ve seen the moon in ages. Was looking in the sea of clouds at some great structures, and want to find out what the object ringed in red was as with the shadows on it made it look like a man made pyramid, which I know it of course isn’t! Hehe! ;) 

05478ACC-C2FB-4573-9CA1-BC1ED98DE8E7.thumb.jpeg.582b0945bed7ceb8b2127a6bb8d82a37.jpeg

Strange one, can't find it named in anything I've got. Hopefully someone with a decent Moon Atlas will pipe up.

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45 minutes ago, Stu said:

Looks fun, how did you get on?

I've been having a really good time with it and learning lots of things in the process. Based on the focal length of my scope and an assumed distance to the moon I made Clavius to be  268.9km across but it is supposed to be 231km. So (accepting some margin of error for where one measures the edge of a crater) I think the effective focal length of my maksutov is longer than the quoted 1,900mm in this session. This tallies with other testing I've done where the effective focal length of the maksutov varies with the position of the primary mirror.  Having a filter wheel in the train pushed the eyepiece back and refocusing with the primary changes the primary position relative to the secondary in particular and this changes the focal length. The lesson therefore (I think) being you can't trust the focal length of a maksutov to stay the same unless you fix all the elements of it in place and never move them.

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48 minutes ago, Paz said:

I've been having a really good time with it and learning lots of things in the process. Based on the focal length of my scope and an assumed distance to the moon I made Clavius to be  268.9km across but it is supposed to be 231km. So (accepting some margin of error for where one measures the edge of a crater) I think the effective focal length of my maksutov is longer than the quoted 1,900mm in this session. This tallies with other testing I've done where the effective focal length of the maksutov varies with the position of the primary mirror.  Having a filter wheel in the train pushed the eyepiece back and refocusing with the primary changes the primary position relative to the secondary in particular and this changes the focal length. The lesson therefore (I think) being you can't trust the focal length of a maksutov to stay the same unless you fix all the elements of it in place and never move them.

Sounds great! Very interesting and yes, compound scopes do vary in focal length depending upon primary position, visually this would happen using a 2" vs 1.25" diagonal for instance.

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Image from tonight’s view of the moon in the Tycho/Clavius quadrant.

91D43B18-F4E9-48BC-8B3A-524B70F80304.thumb.png.05a076a2e8845d3aabbe32bc7d2342e8.png

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That really was a stonking night for lunar.. clouds and flurries now!

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I am chuckling to myself here as most of us normally refuse to go out unless the skies are clear and there's no Moon. Here we are, rare clear night, near Full Moon in the sky and we're hoovering photons like there's no tomorrow!

My dob got its first light in its new setting and it's worked out really well. M42 looked great with E and F stars visible, M44 looked beautiful with its triangular groupings of stars and the Moon looked stunning, as usual.

Feels like the world is alright, now.  :)

 

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31 minutes ago, Beulah said:

I am chuckling to myself here as most of us normally refuse to go out unless the skies are clear and there's no Moon. Here we are, rare clear night, near Full Moon in the sky and we're hoovering photons like there's no tomorrow!

My dob got its first light in its new setting and it's worked out really well. M42 looked great with E and F stars visible, M44 looked beautiful with its triangular groupings of stars and the Moon looked stunning, as usual.

Feels like the world is alright, now.  :)

 

Excellent Sam! Glad the dob is finished and working well. Always good to spot E & F clearly.

 I've been enjoying the moon more than normal, it has looked particularly good recently, steady clear skies and a good phase I guess.

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4 hours ago, Beulah said:

I am chuckling to myself here as most of us normally refuse to go out unless the skies are clear and there's no Moon. Here we are, rare clear night, near Full Moon in the sky and we're hoovering photons like there's no tomorrow!

My dob got its first light in its new setting and it's worked out really well. M42 looked great with E and F stars visible, M44 looked beautiful with its triangular groupings of stars and the Moon looked stunning, as usual.

Feels like the world is alright, now.  :)

 

I didn't even think to look towards the trap.. would have loved ago at the E and F again.. one of them is eluding me currently.. and I cant think which (should write this sort of stuff down)

I have to admit I did enjoy last night, although the dreaded buzz of low power vixen motors really upset me.. but yes for a good time, it felt that all was well in the world.

hopefully some more clear skies to come... never observed in a foot of snow though, how's that work?

Ta

Fozzie

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4 minutes ago, Fozzie said:

I didn't even think to look towards the trap.. would have loved ago at the E and F again.. one of them is eluding me currently.. and I cant think which (should write this sort of stuff down)

Most likely F, I always find it the trickier of the two, closer to a brighter star, I think that's why.

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20 minutes ago, Stu said:

Most likely F, I always find it the trickier of the two, closer to a brighter star, I think that's why.

I seem to recall it was..

Heck i'm still buzzing about last nights views.. so often I read about this high mag and that high mag, and wondering how on earth its achievable, without exotic glass up top or a big mirror behind.. but last night totally floored me, I literally maxed out my equipment at 450x... I mean 450x wowweeeee, id resigned my self to 170-190x being the limit of my set up and skies on good nights..

Last night was probably the best it's going to get (for a long time), I feel a sense of happy achievement that my humble achro produced such a fantastic observation of our near neighbour!

A bit too giddy if i'm honest..

ta

Fozzie

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10 minutes ago, Fozzie said:

I seem to recall it was..

Heck i'm still buzzing about last nights views.. so often I read about this high mag and that high mag, and wondering how on earth its achievable, without exotic glass up top or a big mirror behind.. but last night totally floored me, I literally maxed out my equipment at 450x... I mean 450x wowweeeee, id resigned my self to 170-190x being the limit of my set up and skies on good nights..

Last night was probably the best it's going to get (for a long time), I feel a sense of happy achievement that my humble achro produced such a fantastic observation of our near neighbour!

A bit too giddy if i'm honest..

ta

Fozzie

It's great when it happens! Your picture show how steady the sky was, and that's what made the difference. Nothing wrong with our kit most of the time, it's just the sky not playing ball.

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48 minutes ago, Fozzie said:

I seem to recall it was..

Heck i'm still buzzing about last nights views.. so often I read about this high mag and that high mag, and wondering how on earth its achievable, without exotic glass up top or a big mirror behind.. but last night totally floored me, I literally maxed out my equipment at 450x... I mean 450x wowweeeee, id resigned my self to 170-190x being the limit of my set up and skies on good nights..

Last night was probably the best it's going to get (for a long time), I feel a sense of happy achievement that my humble achro produced such a fantastic observation of our near neighbour!

A bit too giddy if i'm honest..

ta

Fozzie

Keep hold of that 4" F11 StarWave Fozzie, its something special!  X450 WOW! And it looks superb too! :icon_compress:

When i first became interested in astronomy back in 1979/80 I befriended a local amateur who showed me the ropes, and who drummed it into me, that "you can't whack a 4" refractor!" Translated into english, "you might get brighter but youd find it hard to beat the crisp, razor sharp images produced in a good 4" refractor!" I think he had his head screwed on!

I've attached some info regarding the 4" F11 and it is above the average it seems!

5a94157aa9b5f_2018-02-2614_13_52.thumb.png.78ae69c15f528ac2210fe4f2db8edb02.png

 

Edited by mikeDnight
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9 hours ago, Stu said:

Excellent Sam! Glad the dob is finished and working well. Always good to spot E & F clearly.

 

Oh, I was using my recently recommissioned 12"...  :D Very happy reunion with regard to easy set up, etc.

The rebuilt 16" had a quiet first light a few weeks ago (well the whole area heard me yell for joy when M42 came to focus :D )...I need to sort out the blumming alt bearings!! It's getting the time to do it....I do wonder though if self builds have eternal fettling involved as standard...

 

5 hours ago, Fozzie said:

I didn't even think to look towards the trap.. would have loved ago at the E and F again.. one of them is eluding me currently.. and I cant think which (should write this sort of stuff down)

It was your comments about high mags that inspired me to search...thanks.   :)

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Another good evening last night. First time I've had near-still images of the Moon at 250x with my FC-100 and Delite 3mm. Could have taken more magnification, though I'm not sure whether the extra mag would be worth it with a 4" frac - when does dimness outweigh the benefits of turning up the power with a relatively small telescope? 

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12 minutes ago, Highburymark said:

Another good evening last night. First time I've had near-still images of the Moon at 250x with my FC-100 and Delite 3mm. Could have taken more magnification, though I'm not sure whether the extra mag would be worth it with a 4" frac - when does dimness outweigh the benefits of turning up the power with a relatively small telescope? 

I think I would struggle with floaters over x200, but was over x300 with binoviewers on the moon last night and still plenty bright enough :). I guess you are not adding any detail beyond a certain point but the image scale helps.

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I have to admit the on Sunday at high mag the image scale was impressive, did I see more detail at 400x than at 230x it's difficult to say, my previous efforts allowed me to see craters to about 2.2k.. I did look but couldn't say I got anything smaller than that.. and that was wiyh a mag of 180x ish with a 7mm vixen LV.

The image was noticeable dimmer at those high mags. I did notice what appeared to be dim streaks, like looking down a cone radiating from the centre, not distracting but certainly there, they were almost every hour on a clock face if that makes sense.. didn't notice any floaters though.

 

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2 hours ago, Stu said:

I think I would struggle with floaters over x200, but was over x300 with binoviewers on the moon last night and still plenty bright enough :). I guess you are not adding any detail beyond a certain point but the image scale helps.

Stu - what's your binoviewer set up to get 300x on the moon? Presume you're using your FC?

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1 hour ago, Highburymark said:

Stu - what's your binoviewer set up to get 300x on the moon? Presume you're using your FC?

Hmmm, I knew someone was going to ask that! ;) 

I have a slightly bizarre approach to this, but arrived at through experimenting with various kit. Some time ago I purchased a pair of Zeiss converted microscope eyepieces. They are effectively 25mm I believe, and have good eye relief. They are also razor sharp, with low scatter and will barlow to ludicrous levels. I've often wanted a pair of shorter focal length eyepieces to achieve the same mag but the quality has never been the same, even with something like SLVs.

You may have seen my white light solar reports. Under good conditions these are made normally with a x1.7 GPC and then with an AP Barcon with two extension tubes. I work on the assumption that this gives me x4, giving an effective scope focal length of 5032, mag of around x200. The detail is quite spectacular when the seeing is good.

Last night, I used a x2.6 GPC with the same setup, resulting in x300. I do have some uncertainty over exact numbers due to the effect of additional optical path length of the binoviewers. What I know is that whether it was lower or higher the results were fantastic.

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33 minutes ago, Stu said:

Hmmm, I knew someone was going to ask that! ;) 

I have a slightly bizarre approach to this, but arrived at through experimenting with various kit. Some time ago I purchased a pair of Zeiss converted microscope eyepieces. They are effectively 25mm I believe, and have good eye relief. They are also razor sharp, with low scatter and will barlow to ludicrous levels. I've often wanted a pair of shorter focal length eyepieces to achieve the same mag but the quality has never been the same, even with something like SLVs.

You may have seen my white light solar reports. Under good conditions these are made normally with a x1.7 GPC and then with an AP Barcon with two extension tubes. I work on the assumption that this gives me x4, giving an effective scope focal length of 5032, mag of around x200. The detail is quite spectacular when the seeing is good.

Last night, I used a x2.6 GPC with the same setup, resulting in x300. I do have some uncertainty over exact numbers due to the effect of additional optical path length of the binoviewers. What I know is that whether it was lower or higher the results were fantastic.

Thanks Stu. I have pairs of 25mm Fujiyama orthos and 20mm, 15mm and 11mm TV plossls - all for solar with a WO binoviewer - but doesn't quite have the flexibility of a Baader binoviewer. Am waiting to see what the new Maxbright replacement will be like.

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9 hours ago, Highburymark said:

Thanks Stu. I have pairs of 25mm Fujiyama orthos and 20mm, 15mm and 11mm TV plossls - all for solar with a WO binoviewer - but doesn't quite have the flexibility of a Baader binoviewer. Am waiting to see what the new Maxbright replacement will be like.

Yes, the Baader Mark IV I have can be used with T2 quick changers. To change power I usually just have to add or remove an extension, the eye pieces never change.

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