New D&G 5" F15 Refractor

[F15Rules]

Thanks again guys 

Wonder of wonders I had a short (40 minutes) first light last night and got a quick view of 4 objects: Mars, Jupiter, Vega and Castor.

The weather here has been lousy all week for astronomy: yesterday evening the skies cleared before it was dark but it was around 11pm before I could get outside. The transparency was good, but the seeing was pretty poor..the star test showed very good concentric rings either side of focus but the image was "scintillating" a lot..I'd say the seeing was no better than 4 to 5 on the Pickering scale (see Damian Peaches animation here: http://www.damianpeach.com/pickering.htm) which rates at best as "Fair" (5) or "Poor" (4).

To be honest I was just delighted to get the scope up and running and looking through it ("her"...I'm thinking of calling her Andromeda, is that naff??  ...my wife says I should call "him" "Plutarch"...what do YOU think?). In such a short session I couldn't do much detailed observing but I'd make the following comments:

• Great contrast, good dark sky background
• Narrower FOV than I am used to, but with c1900mm Focal Length even my 2" 50mm ep gives x38. I did find that my 40mm Reverse Kellner gave a really nice split of Castor, which was very low down by c. midnight.
• Very little false colour, even at quite high powers. With the longer FL 2" eps it is effectively non-existent on Vega, just the merest tint of violet and intermittently at that. Also, Vega's 10th magnitude faint companion was very clearly seen with direct vision, even allowing for the glare from Vega itself.
• I tried, just for fun, some "straight through" viewing. With Vega still fairly low at around midnight, the scope angle was nicely set for me to view Japanese style comfortably while sitting in a garden chair. I must say, it seemed to me that the view straight through was even less affected by CA...has anyone else observed this? My diagonals are both good quality, and Opticron 2" dielectric and a TS Optics 1.25" dielectric, so I doubt they add much colour, but it did seem that the straight through view was just slightly "purer"...if that makes sense. I must pursue this further.
• Mars - this was not a great night for planets, even though transparency was good. But I could see the north polar cap very well defined, with a large dark mass right at the opposite side of the disk (ie at the bottom of the field, while the polar cap was at the top). The sharpness improved slightly with a filter, but I'm sure the atmosphere was at fault: Jupiter was quite a lot lower than Mars and was similarly not a very steady object. But I could see 4 belts quite comfortably and the colour of the planet looked very good, no CA that I could see at all. Any magnification over about x180 seemed to result in a more mushy, unsteady image.
• Castor presented a very short but sharp view as two pure white bullseyes with black sky between them at just x48 magnification..before I could try anything higher power, the clouds had completely rolled in and I had to call it a night at 12.15am.

This isn't in any way a proper first light report, that will have to wait, but I did get enough tantalisingly good views to believe that this scope will be all I would want it to be. The scope was easy to handle and tracked nice and smoothly with my standard motor drives. It was fairly breezy last night and up to x200 or so the mount handled it ok. In calm weather I'm sure I could get to over 300x with a steady view.. I'm a happy chap!

regards to all,

Dave

[nightfisher]

good to here you have been out with the scope, look forward to a proper report when and if the weather ever improves

[John]

All very promising Dave 

I'd completely forgotten that Vega had a companion star. I must look out for it when next out viewing.

I must have a go at straight through viewing too. 

[DaveGibbons]

Well that's some scope you have arrived at Dave.  I have drooled over D&G achro's many times ! I hope it is everything you dreamed of , you being a refractor nut  'n' all. Good to see the old wooden legs holding up (mount not your's).  It's surprisingly light for it's size and is a beautiful bit of kit, be interesting to see how it performs on a great night.

regards

Dave

[Dude_with_the_tube]

very interesting Dave and by the sound of it,looks like your scope is performing brilliantly.i will certainly try a straight through observation method too and will report back my findings.

Clear skies.

[F15Rules]

Hi again guys

Well, I've settled on the name Andromeda for the scope...apparently in Greek it means Ruler of Men..Nuff said!!

Phil, although the lens cell is not collimateable as we normally define the term, the letter of instruction to the original buyer says that fine collmation can be adjusted by loosening off the  mounting screws at the front of the tube and gently moving the lens to or fro as needed. Sounds a bit Heath Robinson to me so I will leave well alone. I got a short view of Denebola last night just to look at intra and extra focal images and they look very nice. Seeing was slightly better but still only fair. I think the Jetstream is doing us no favours right now! I also had a quick look at Jupiter (around 8.30pm).. the sky was much "muckier" than previously but definitely a little steadier.. I could see very distinctly one of the moons appearing to come around from behind the planet and over about 20 minutes it moved definitely further from the planet...and it was definitely, absolutely a tiny but perfectly formed disk! The other thing I have been struck with is the very natural looking colour of the planet...no yellow, no violet, just a nice, pale creamy coloured globe with bands which are clearly irregular and with details trying to show themselves..

Dave, your tripod is superb and I will never sell it. It just soaks up vibrations and I'd recommend a good solid wood tripod to anyone over even a good steel one like the CG5 2"...the difference is very apparent.

Good to see you back in the hobby Dave, and your Istar project gave me the inspiration to look out for a long 5" frac...little did I dream that it would be a D&G!

I've also played around with the balance of the scope more and I've managed to get it to a really fine balance with just one 5kg counterweight instead of the 10kg total she was carrying in the photos above.  I can push the scope about literally using just one finger..This has only been possible because of the longer than standard counterweight bar on the CG5...it's about 5" or so longer than a standard bar, and the 5kg weight sits right at the end of the bar. But much easier to carry the rig outside from garage to drive and actually surprisingly steady...the worst part is getting very fine focus at high power, once you have the "snap" the drives then track really smoothly.

Just want a long, very calm, very steady night now!

cheers

Dave

[GuillermoBarrancos]

Wow! Just noticed this thread! What a fantastic looking Scope! What a beast!

[F15Rules]

I sent an email to Barry Greiner of D&G to ask some questions about Andromeda (aka D&G F15  ). I only sent it last evening and to my surprise this morning I had a reply from the great man himself!

I'm pleased to say that Barry confirmed that the whole tube was built by D&G and the objective #0575 was supplied, in it's OTA tube, to Osborne Optics...in May 1991!     ...so the scope is actually 23 years old! Of course this also means that Osborne optics had it in their stock for some 9 years, no wonder they went out of business...

D&G only started trading in 1987 so this is therefore quite an early scope which for me adds to it's interest and appeal. Barry advised that soon after 1991 they introduced the fully collimateable cells, with powder coatings on the tubes and rings, and later again (I think about 2007/8) they introduced the Astrophysics 2.7" focuser as standard.

Barry further advised that my scope could be adapted for the AP focuser they use now, but would need a new backplate to be machined...hmmm, something to think about for the future perhaps.

Still living in hope of a clear steady night... 

Dave

[John]

Great response from Barry 

It's so nice to have that additional bit of background on your scope and it's history. It's nearly vintage !

[A McEwan]

Back in the days before I ever owned a telescope, I received a catalogue from Osborne Optics, which is still in my collection somewhere. This was in the days before the Internet, and the 2 page review of the Intes MK-67 included would inspire me for many years to come...

23 years old is not bad, Dave, but my Swift 839 is 50 this year. Yah boo sucks!

Ant

[Peter Drew]

I'll raise you Ant, I have a 3" refractor over 200 years old! 

[F15Rules]

Isn't it funny how it's kind of "sexy" the older a scope is, adding to their appeal. Why doesn't that apply to humans though...specifically 58 year old males??  

I went back to Barry at D&G to ask about the lenses and whether the specs or manufacturing processes used have changed over the years. I also asked whether the original R&P focuser (which I actually really like) was built in house or bought in. He replied (very promptly again - top man) that the lens in my scope is exactly the same spec and finish as those they put out now, and that the focuser was bought in from another company (didn't say who, but if it was the early 1990's I reckon it would almost certainly be from another USA company as this was before the Chinese/Far East stuff took off.

All the info really adds to the charm and interest of the scope. I'd love to know if there are any other D&G owners in the UK out there?

It's really great to know that traditional, long focus refractors are alive and well: I know that Istar scopes have quite a following now in the UK and that several SGL members have them, as well as many vintage F10-F15 refractors and of course the beautiful and now sadly discontinued Skylight F13/15's.

As John said to me, there is just something about sitting at the end of a long tube under the stars..  

Dave

[F15Rules]

Last night we had a lovely clear night for the first time it seems for ever...

The seeing was better too, at least fair to good with moments of good steadiness.

The only downside was the full Moon, which although not that high still dominated the entire sky with a bright glow  ..

I did at least get an hour to view a few objects with the D&G F15 (aka Andromeda  ), and the more I use this scope (not nearly enough, so far), the more I like it.

First view was of Delta Cygni. This isn't an easy double, although I have split it in the past with a good F16 achromat, but normally I've always needed 4" of glass to be sure of the split (something to do with our very unreilable seeing too I think). Well, last night there was the most lovely pair of bullseyes, one very bright, the other much dimmer, but each very distinct and very dark sky separating them. I should just mention at this point the view with a recently acquired Pentax 8m XF was superb. This ep gives me x224 on the D&G and was just crystal clear. Just for a laugh I put the XF in a nice AE barlow to give x448  ..and the image held up really well. No CA to speak of, and a very clear image given the magnification involved, but the seeing was much better suited to the XF at 8mm by itself. But it's great to know the scope can take that kind of magnification should the conditions allow it. And bear in mind this was with a Full Moon glaring down!

Next was Albireo, a favourite of most people, and it was just beautiful with a Tal 25mm plossl giving x76. I also used a Meade 4000 SWA 24.5mm and that view was just superb..wide expanse of sparkling stars framing the orange and light blue/green of Albireo perfectly. If only this had been against a dark moonless sky...I must be patient!

Lastly (yes, I spent my whole hour on just 3 objects) was Saturn. Very close to the Moon last night but this was simply the very best view of Saturn I have ever had, bar none. At x224 again with the Pentax XF 8mm the Cassini Division was sharply defined around almost the whole planet, with definite signes of a darker, thick band across the planet, and two Moons, Titan well away from the planet and a much fainter one close in (anyone know which one that was?). Given the lowish altitude and the proximity of the full Moon, I am delighted with the views I had last night...just whet's my appetite for a proper, long dark night session.

Just one other comment: I recently went to Norfolk for the weekend and was lucky enough to have a very clear and Moonless sky that night.. I took a lovely old Polarex 60mm F15 with me and was amazed at how much more it showed that night than back home in the Midlands. It just got me thinking, if, or when, I could get the big frac out to skies like that, how much more could it show me? I do think the sky darkness for people like me who are used to orange glows in most directions, is still a big surprise when you can get out to a dark site. Roll on retirement!

cheers

Dave

[John]

Lovely report Dave 

Funny that you should mention Albireo. I've had a couple of sessions with my big refractor but the view of Albireo is the one that really sticks in my mind. I've observed this colourful pair many times over the years as I'm sure you have, but a big long refractor does seem to add something indefinably satisfying to the view

On dark skies, I took my old Intes 6" mak-newt to the SGL star party a couple of years back and we were blessed with some lovely dark skies that year. The 6" scope was showing galaxies at least as well as a 10" did at home, probably better really.  It's worth making the effort !

[nightfisher]

Last night we had a lovely clear night for the first time it seems for ever...

The seeing was better too, at least fair to good with moments of good steadiness.

The only downside was the full Moon, which although not that high still dominated the entire sky with a bright glow  ..

I did at least get an hour to view a few objects with the D&G F15 (aka Andromeda  ), and the more I use this scope (not nearly enough, so far), the more I like it.

First view was of Delta Cygni. This isn't an easy double, although I have split it in the past with a good F16 achromat, but normally I've always needed 4" of glass to be sure of the split (something to do with our very unreilable seeing too I think). Well, last night there was the most lovely pair of bullseyes, one very bright, the other much dimmer, but each very distinct and very dark sky separating them. I should just mention at this point the view with a recently acquired Pentax 8m XF was superb. This ep gives me x224 on the D&G and was just crystal clear. Just for a laugh I put the XF in a nice AE barlow to give x448  ..and the image held up really well. No CA to speak of, and a very clear image given the magnification involved, but the seeing was much better suited to the XF at 8mm by itself. But it's great to know the scope can take that kind of magnification should the conditions allow it. And bear in mind this was with a Full Moon glaring down!

Next was Albireo, a favourite of most people, and it was just beautiful with a Tal 25mm plossl giving x76. I also used a Meade 4000 SWA 24.5mm and that view was just superb..wide expanse of sparkling stars framing the orange and light blue/green of Albireo perfectly. If only this had been against a dark moonless sky...I must be patient!

Lastly (yes, I spent my whole hour on just 3 objects) was Saturn. Very close to the Moon last night but this was simply the very best view of Saturn I have ever had, bar none. At x224 again with the Pentax XF 8mm the Cassini Division was sharply defined around almost the whole planet, with definite signes of a darker, thick band across the planet, and two Moons, Titan well away from the planet and a much fainter one close in (anyone know which one that was?). Given the lowish altitude and the proximity of the full Moon, I am delighted with the views I had last night...just whet's my appetite for a proper, long dark night session.

Just one other comment: I recently went to Norfolk for the weekend and was lucky enough to have a very clear and Moonless sky that night.. I took a lovely old Polarex 60mm F15 with me and was amazed at how much more it showed that night than back home in the Midlands. It just got me thinking, if, or when, I could get the big frac out to skies like that, how much more could it show me? I do think the sky darkness for people like me who are used to orange glows in most directions, is still a big surprise when you can get out to a dark site. Roll on retirement!

cheers

Dave

Good report Dave, you should think about getting to a star party, bring the D & G along, looks like there will be a good camp at Lincoln (badger farm) in August, really good skies out there

[Stu]

Lovely report Dave, very glad it is living up to expectations. Sounds like you had a little better seeing than I did last night, but I had some half decent views of Saturn too. The second moon you saw was, I think, Rhea. I picked up Dione and Tethys too but they were very faint.

I quite agree with you, getting these scopes under a really dark sky is something that I really would love to do. It seems pretty challenging logistically and trying to arrange the weather aswell is near impossible. We must make the effort though, it will be well worth it.

Cheers,

Stu

Sent from my iPhone using Tapatalk

[A McEwan]

Glad you had a chance to get some proper viewing done with Andromeda Dave!

I'm sure you'd be very impressed from ultra dark skies, but does a 5" f15 really count as grab'n'go?!?

Ant

[F15Rules]

You're right John, and I do want to try to go to one or two dark sites and in retirement (a little way off yet, sadly) I would love to live in a more rural area...

You sound really positive about your Mak-Newt and I've certainly read good things about them..and you know I really like Intes gear..

Jules, I've pm'd you to get details of the Lincolnshire event, I'd like to come if the date doesn't clash with other "stuff"...

cheers
Dave

[Jim Steele]

Really good report Dave, sounds like you have yourself a fantastic scope.

[Marki]

Excellent report Dave. Glad the scope performs as well as it looks! Hopefully I'll get to have a look through it if you get to the Lincs event Jules mentioned. I'm hoping to go, and I'll bring my Skylight f13 and my Tal125r - be great to compare those with the D&G.

[F15Rules]

Cheers guys:-). Would you believe it we had two clear nights on the trot at the weekend and I couldn't get out as we had visitors / family stuff on! I've just acquired a Leica Various Zoom to replace most of my fixed length EPs. Had a 10 min peek at Saturn last night and looks very promising..more to follow soon..

Dave

[Dude_with_the_tube]

sounds like one happy man with a big frak

cracking reports and cracking scope Dave!

[Grotemobile]

Here is a pict of my F10 scope on the CG-5.

Yours is twice the length of mine.Must be a bit

of a hand full.Under rated mount the CG-5.

Had my C11 on it before this.

Steve

[F15Rules]

Cheers Dude ! (Good grief, starting to sound like our USA friends on CN  

Steve, lovely set up there. That looks like  Vixen SP102M if I'm not mistaken?

Had a couple of those, lovely scopes, set the pace back in the 1980s/early 90s with great optics

Dave

[Grotemobile]

Cheers Dude ! (Good grief, starting to sound like our USA friends on CN  

Steve, lovely set up there. That looks like  Vixen SP102M if I'm not mistaken?

Had a couple of those, lovely scopes, set the pace back in the 1980s/early 90s with great optics

Dave

Your dead right is is.I bought it s/hand about 5 years ago.

I have had a lot of use out of it .The optics are not coated

on this.Just clear glass.Strange.

Steve