11297 replies to this topic

[ccwemyss]

4mm is just too short for a straight eyepiece. I've never seen a top notch one. My best in that class is a 4.7mm UWA, but it's got a built-in Barlow and 3 or 4 hundred lenses.

 

-drl

My Pentax XP 3.8 is incredibly sharp. It’s what I turn to when the conditions allow, to push my Pentax achromatic to 80x per inch on planets or the moon. 
 

Chip W.

[Bungee]

You need a good chart accurate to the hour, then sweep around until you've got the star field in your finder. Neptune is unmistakable by its color, like no star. It is one of my favorite things in the sky - no person will ever live for a full orbit.

 

-drl

 

I'm pretty thorough in my prep work, so I'm confident I was looking in the right place. I was scanning with a 35mm plossl and once or twice thought I had a dark blue freckle in my crosshairs. But at mag 7.5 I just wasn't sure.  Maybe Chas called it and I need a little more pow wow. I've got an Svbony 26 wide that isn't horrible.

Better ep's are next on my wish list.

[deSitter]

I'm pretty thorough in my prep work, so I'm confident I was looking in the right place. I was scanning with a 35mm plossl and once or twice thought I had a dark blue freckle in my crosshairs. But at mag 7.5 I just wasn't sure.  Maybe Chas called it and I need a little more pow wow. I've got an Svbony 26 wide that isn't horrible.

Better ep's are next on my wish list.

No, you need an accurate chart and to know that Neptune is a blue that no star can match.

 

-drl

[deSitter]

My Pentax XP 3.8 is incredibly sharp. It’s what I turn to when the conditions allow, to push my Pentax achromatic to 80x per inch on planets or the moon. 
 

Chip W.

Also a N element eyepiece for N >> 2 or 3.

 

XP, N=6.

 

-drl

[ccwemyss]

Also a N element eyepiece for N >> 2 or 3.

 

XP, N=6.

 

-drl

XP 3.8 = 5 element, not barlowed. The 8mm XP has 6 elements. If N must be  <4, then the 4 or 5-element Plossls, and the 4-element Abbe Ortho are also not "straight eyepieces."

 

So "straight eyepiece" means a primitive design that delivers poor performance at short focal lengths, like a Ramsden, Huygens, or Kellner. Given that definition,  your original statement, "4mm is just too short for a straight eyepiece," is correct. 

 

Sorry I misunderstood. I thought that it meant a simple design that doesn't use a built in barlow. 

 

Chip W. 

[Senex Bibax]

I had an enjoyable couple of hours yesterday evening with my Meade 310 and a 32mm Super Plössl eyepiece. It was a cool, breezy evening (no bugs) and the skies west of Ottawa were very clear for a change. The Milky Way was easily visible stretching from Sagittarius over the zenith and across to Cassieopia. By the time I packed up after 10 PM the temperature was already down to 8 - 9 degrees Celsius.

 

I got some good views of Saturn rising in the east, with very thin rings. I also got some views of a few bright galaxies, namely M31, M81 and M2, but best of all were the globulars. I had fine views of M22, M3, M5, M80 and M15. M4 was difficult because of its low altitude and proximity to Antares, and Sagittarius' low altitude meant that I could only pick out M22,m but all in all it was a successful outing by my usual standards.

[deSitter]

XP 3.8 = 5 element, not barlowed. The 8mm XP has 6 elements. If N must be  <4, then the 4 or 5-element Plossls, and the 4-element Abbe Ortho are also not "straight eyepieces."

 

So "straight eyepiece" means a primitive design that delivers poor performance at short focal lengths, like a Ramsden, Huygens, or Kellner. Given that definition,  your original statement, "4mm is just too short for a straight eyepiece," is correct. 

 

Sorry I misunderstood. I thought that it meant a simple design that doesn't use a built in barlow. 

 

Chip W. 

There is no reason you couldn't make an accurate 4mm simple 3- or 4-element eyepiece but they just don't turn up often. Maybe the premium ones are better. Probably it gets very difficult to make small achromats and triplets.

 

-drl

Edited by deSitter, 03 September 2024 - 10:30 AM.

[jgraham]

Tonight I was able to see T CrB through the Unitron 510. It was an easy star-hop from Epsilon CrB. Since there are no bright stars in this area T CrB should look gorgeous when it erupts. Since you will be looking directly at an unshielded thermonuclear event I expect it to be a brilliant blue/white. Should be fun!

[ElGran]

I saw the Veil nebula for the first time, very impressive. Other nebulae too, like M57, M27, M8, M20, M16, M17.

I tried Barnard's galaxy but it was impossible to distinguish anything, perhaps it's surface brightness is too low. It  was a Bortle 3-4 location.

[deSitter]

I saw the Veil nebula for the first time, very impressive. Other nebulae too, like M57, M27, M8, M20, M16, M17.

I tried Barnard's galaxy but it was impossible to distinguish anything, perhaps it's surface brightness is too low. It  was a Bortle 3-4 location.

What scope? f/ratio? Exit pupil?

 

-drl

[highfnum]

its been a while 

criterion RV6

Jupiter

simple B&W

 

[vineyard]

A lovely night in Bortle 4 SW Portugal.  An old Vixen ED102SS on an old EzTouch mount, with a 22T4 and 31T5.  Hb and Oiii filters (newly acquired from a fellow CNer and arriving in perfect timing), so of course went looking for the Veil and NAN - with the invaluable help of a PiFinder ofc.  Found them both, and it was great seeing them - first time for me w/o NV!  The kids were also blown away, especially once they realised what the Veil literally was.

 

The bigger exit pupil of the 31T5 definitely makes a huge difference - that is one heavy EP though, scope needed rebalancing.  Seeing the entire Veil - including the brighter bits of Pickerings Triangle - in one FOV was awesome.  When I get home I am going to have to image the Veil to show the kids what they were looking at.

 

And then just went for a wander hither and thither for a bit before packing up.  There's a lot of Hb up there!

 

I may try again tonight with a TV55 and afocal NV to see what the difference is.

[deSitter]

Tonight I was able to see T CrB through the Unitron 510. It was an easy star-hop from Epsilon CrB. Since there are no bright stars in this area T CrB should look gorgeous when it erupts. Since you will be looking directly at an unshielded thermonuclear event I expect it to be a brilliant blue/white. Should be fun!

Make sure to use your Baader No-Trino neutrino filter!

 

-drl

[ElGran]

What scope? f/ratio? Exit pupil?

 

-drl

200 mm reflector, f/6, 25mm plossl eyepiece

[deSitter]

200 mm reflector, f/6, 25mm plossl eyepiece

So 48x and 4mm exit pupil. There is always a question about what exit pupil provides the best view of nebulosity. On paper you want the largest your eye can admit - 5mm to 7mm based on age. But people do report better results at 3mm and 4mm exit pupil.

 

-drl

[Senex Bibax]

I had an enjoyable couple of hours yesterday evening with my Meade 310 and a 32mm Super Plössl eyepiece. It was a cool, breezy evening (no bugs) and the skies west of Ottawa were very clear for a change. The Milky Way was easily visible stretching from Sagittarius over the zenith and across to Cassieopia. By the time I packed up after 10 PM the temperature was already down to 8 - 9 degrees Celsius.

 

I got some good views of Saturn rising in the east, with very thin rings. I also got some views of a few bright galaxies, namely M31, M81 and M2, but best of all were the globulars. I had fine views of M22, M3, M5, M80 and M15. M4 was difficult because of its low altitude and proximity to Antares, and Sagittarius' low altitude meant that I could only pick out M22,m but all in all it was a successful outing by my usual standards.

Last night I had a near repeat observing session, this time with my Celestron C-6R 6" refractor. Conditions where slightly less clear than Monday night. I mostly observed the same objects as Monday, and the big refractor was especially good for observing globular clusters compared to my smaller scopes. Objects viewed included Saturn, galaxies M31, M110, M81 and M82, and globular clusters M2, M3, M5 and M22. M22 may be the biggest, but I found M2 and M5 the most pleasing to view.

[davidmcgo]

In spite of a whole bunch of smoke blowing over from a fire in Mexico around sunset, the air smelled clean and no ash was on my car, so I took a gamble and set up the 1973 C14 I bought from Woodsman since the next few nights are forecast to be clear and dry and my back has recovered from my plumbing repair a few weeks ago.

 

Things cleared up nicely, and I tracked down NGC 6905 in Delphinus and NGC 7027 in Cygnus after the usual visits with M57, M13, M15, and M2.  M57:in this scope with a 32 mm TV Wide Field shows an interesting hue, it does not seem like a colorless grey but is hard to describe like it has some purple and green hint to it.  M27 was huge in this eyepiece and showed a pronounced apple core shape.  I was not using a nebula filter and my backyard is far from a dark sky site.  But really interesting to see how the same exit pupil shows the object much more obviously and detailed compared to a smaller scope like my C8, even in light polluted skies.  NGC 7027;is a really strong blue color planetary and a bit elongated.  NGC 6905 gets called the Blue Flash or something like that but is much lower surface brightness so just looks more grey.  But it is in a really field of stars.

 

M2 and M15 I really like.  The stars are denser than M13 and fainter but the 14” really pulled them in.  I checked out Saturn rising for a bit and was nice but a bit turbulent so I put the TeleGizmos 365 over the scope and grabbed a few hours of shuteye with my alarm set for 0245.

 

So out again this am, Jupiter and Mars beckoning.  Orion rising.  But not the super stable seeing I was hoping for.  Jupiter snaps with detail for split seconds with a Moon shadow right above the Great Red Spot, another moon ingress in the disk, but fuzzing out a lot so I stuck with the 16mm Konig.  Mars needed more power in spite of the seeing so I used the 10.2mm ortho for it, with occasional glimpses of the North Polar Hood and Syrtis Major, so not a complete waste.  I also checked out Omicron 2 Eridani, NGC 1535, M42, and M76.  M76 was really nice in the 32mm eyepiece, really punched through the light pollution better than my 15” Obsession does without a filter. The Dob isn’t really baffled as well.

 

Around 0400 some monsoon clouds started coming in and the humidity went up, so I cleared the dew off the corrector with a hair dryer on low, capped and covered the scope and will be out again tonight.

 

Dave

[deSitter]

In spite of a whole bunch of smoke blowing over from a fire in Mexico around sunset, the air smelled clean and no ash was on my car, so I took a gamble and set up the 1973 C14 I bought from Woodsman since the next few nights are forecast to be clear and dry and my back has recovered from my plumbing repair a few weeks ago.

 

Things cleared up nicely, and I tracked down NGC 6905 in Delphinus and NGC 7027 in Cygnus after the usual visits with M57, M13, M15, and M2.  M57:in this scope with a 32 mm TV Wide Field shows an interesting hue, it does not seem like a colorless grey but is hard to describe like it has some purple and green hint to it.  M27 was huge in this eyepiece and showed a pronounced apple core shape.  I was not using a nebula filter and my backyard is far from a dark sky site.  But really interesting to see how the same exit pupil shows the object much more obviously and detailed compared to a smaller scope like my C8, even in light polluted skies.  NGC 7027;is a really strong blue color planetary and a bit elongated.  NGC 6905 gets called the Blue Flash or something like that but is much lower surface brightness so just looks more grey.  But it is in a really field of stars.

 

M2 and M15 I really like.  The stars are denser than M13 and fainter but the 14” really pulled them in.  I checked out Saturn rising for a bit and was nice but a bit turbulent so I put the TeleGizmos 365 over the scope and grabbed a few hours of shuteye with my alarm set for 0245.

 

So out again this am, Jupiter and Mars beckoning.  Orion rising.  But not the super stable seeing I was hoping for.  Jupiter snaps with detail for split seconds with a Moon shadow right above the Great Red Spot, another moon ingress in the disk, but fuzzing out a lot so I stuck with the 16mm Konig.  Mars needed more power in spite of the seeing so I used the 10.2mm ortho for it, with occasional glimpses of the North Polar Hood and Syrtis Major, so not a complete waste.  I also checked out Omicron 2 Eridani, NGC 1535, M42, and M76.  M76 was really nice in the 32mm eyepiece, really punched through the light pollution better than my 15” Obsession does without a filter. The Dob isn’t really baffled as well.

 

Around 0400 some monsoon clouds started coming in and the humidity went up, so I cleared the dew off the corrector with a hair dryer on low, capped and covered the scope and will be out again tonight.

 

Dave

Neat! Any color in M27 (Dumbell)?

 

I've seen that faint purple and green with my 10" on M42. It's hard to describe, like the electric color of the sky during twilight on a super-transparent day. Your color receptors are working, but there isn't much to bite on!

 

-drl

[davidmcgo]

M27 just looked grey.

 

Dave

[ccwemyss]

Had the Pentax 100 out at school for an observing evening with the class (only four came out -- nearly half the class is away on exchange, and several are sick). Mostly a constellation identification lesson, but then showed them Alcor/Mizar A/B, M13, Alberio, M31, M57, and Saturn. I let them observe first, without explanation, then again after. Also started with a 40mm on M13, then stepped up to 9mm so they could experience the "fuzzy star" being resolved into many stars. Some saw the colors in Alberio right away, while others needed a second look. Despite the angle of the rings, they all recognized Saturn. 

 

Chip W. 

[BKSo]

Another dark sky session after months of rain and clouds. The transparency last night was very good, NELM about 6.0, but the site was dewy, even my insulation and dew fan couldn't keep the telescope dew few. Interestingly the site was just above ground fog.

 

M69 Quick look with 40 PL, easy, small at this magnification.
NGC6652 Also quick look with 40 PL, similar to M69.
NGC6723 Used 40 PL and 58 PL, very bright, seen just above horizon. Neighboring NGC6729 not seen.
M8 Quick look with 58 PL + uhc to test eyepiece.
M20 Small, round nebulosity with 58 PL + uhc, no detail really.
M17 Used 58 PL + uhc, still ‘swan’ shaped.
M16 Nice and bright with 58 PL + uhc. Shape clear but no dark nebulosity or other fine detail.
NGC6716 Nice, rich OC.
Cr394 Next to NGC6716, bigger, brighter but looser and less rich. Triangular shaped.
NGC6822 Best with 40PL. Very faint and large. Brightening repeatedly glimpsed when moving the telescope. Roughly elongated north-south.
NGC6818 Close to NGC6822. Confirmed with uhc filter. Maybe a hint of being non-stellar with 15 UW.
M31, M32, M110 Returned after a dew break, great view with 58 PL, some hint of photographic details.
NGC185 Used 40 PL, faint but quite large, easy with averted vision. Slightly elongated.
NGC147 Surprising best with 25 GF (Leica  Periplan10x/20). Difficult, comparable with NGC6822 in terms of apparent surface brightness, but much smaller. Visible with averted vision when moving the telescope.
M74 Easy. Round blurry disk.
NGC772 Near M74. Rather easy with 25 GF and averted vision, comparable to NGC185 but much smaller.
NGC253 Used 40 PL. Low in the sky. Seen with direct vision. Elongated and no detail.
M45, NGC1435, NGC1432 Returned after another long dew break. Observed the Pleiades to test the 58 PL, a DIY job made from lenses that would be used as binoculars objectives. The scatter of the 58 PL seemed to be comparable to the 40 PL and worse than the 64 D (which I did not have with me) but the diagonal was dirty. Nebulosity seen with averted vision.
M42, M43 Used 58 PL + uhc. Large ‘northern wing’ but not much ‘southern wing’.
NGC884, NGC896 Used 40 PL .Sky began to brighten.
NGC7789  Nice view with 25 GF. Misty.
M35 Great view with 25 GF. Hundreds of stars.

[Paul Sweeney]

Last night there was a short period of clear skies as a rain front arrived. I took the Novolux 415 60mm refractor on my GP mount out for a look. I put in the adapter and was using 1.25" eyepieces.
First up was Saturn, low in the southeastern sky. Not a whole lot of detail, just a yellow ball with a stripe in front of it. At 69x (6mm LV) I was able to pick out one moon.

On to Vega, which was quite nice and had very little color. I trird to split the double double, but no luck. M57 was dim but clearly a donut. Albirio was also a nice sight.

The clouds forced me to the eastern sky, so I stopped in at M31, and I was surprised at how much I could see of it using a 23mm 62° aspheric eyepiece.

The double cluster was clearly visible, though not very impressive. Thin clouds were starting to obscure it.

Last up was Eta Cass. I have looked at this pair many times, but this was the first time that the secondary star actually showed a deep, rich burgundy color. I was impressed!

Edited by Paul Sweeney, Yesterday, 04:05 PM.

[Bomber Bob]

Bonus Sunset Session - a thin clear lane opened up long enough for me to grab the FC-76 and get some excellent views of The Crescent Moon at 240x (LV 2.5mm).  Confused Jake, as I set it up in one of his favorite back-scratching spots on the lawn (he's young & still learning about our insane obsession).  Low as it was, the FC kept it sharp until the Moon dropped to about 15* or so...

 

Tough to Beat a Tak...