Solar Zoom Eyepiece

[bomberbaz]

Looking for an eyepiece for my lunt white light viewing. I am using a 80mm aperture FL600 OTA so realistically I do not want to go above x160.

Had a nosey at some options including:

celestron 8-24,

Skywatcher 7-21 or 8-24,

OVL hyperflex 7.2-21.5,

Baader Hyperion 8-24 

Lunt 7.2-21.5.

So obviously the OVL is a copy of the lunt and the SW / celestron 8-24's are along the same lines as the baader zoom.

My aim is to get close into the sun to bring out the granulation, a 4mm ep gives me x150, which is why the above options are being considered for use with a barlow which I already own.

Costs vary a very lot for the above. The SW 7-21 comes in around 40 quid but the baader is topping £180. I don't mind spending but not without good reason. So although the Lunt zoom is well thought of, is the extra near 100 quid over the OVL worth it.

Advice, personal experience and opinions please people. 

TIA, Steve

[John]

I use a 7.2 - 21.5 zoom mostly for nighttime and occasionally when I do solar white light. I've been quite impressed by it. A touch narrow at the 21.5mm end (<40 degrees) but it does widen out to around 55 degrees at the other end.

Mine seems to be a clone of the Hyperflex and Lunt zooms. Here I have the Baader 2.25x barlow attached which makes it a useful 9.4mm - 3.2mm high power zoom:

 

[johninderby]

The HYPERFLEX-7E1 7.2MM-21.5MM zoom is identical to the Lunt. I have the TS version and it is a very good zoom for solar. Not the very best but good though.

The Baader zoom is a little bit better but not a lot of difference. 

[NGC 1502]

Hi Steve.  I’ve done quite a lot of Ha solar observing over the past 12 years with - Coronado PST, Coronado 40, Lunt 35, Lunt 50, Lunt 60,  Solarscope 50 from Isle of Man.  At various time I’ve used several zooms, TeleVue 8-24, Lunt 7.2-21.5, and Skywatcher 7-21.

All of the zooms I found much more alike than different. The standout top value was the SW 7-21, I really couldn’t detect a problem, the amazing low price belied its excellent performance.  This cheap zoom performed poorly on Newtonians used at night, but for Ha use was excellent.

Ed.

 

[michael.h.f.wilkinson]

I used to have the Lunt, which was pretty good, but had shorter eye relief than I need (with my glasses). I now have a William Optics 7.5-22.5 mm Zoom II. It is no longer sold by WO, but the Opticstar seems to be a clone:

http://www.opticstar.com/Run/Astronomy/Astro-Accessories-Telescopes-Opticstar.asp?p=0_10_5_1_8_331

Really nice zoom EP, with 18.0-19.5 mm eye relief

[Louis D]

I took my Celestron Regal 8-24mm zoom to Nebraska to view the partial and total phases of the 2017 eclipse in my ST80.  It worked really well for both.  It's also sold with Olivon spotting scopes.

[Solar B]

I’m a big fan of the Hyperion zooms 

for solar , having used the mk2 , 3 and 

now 4 exclusively for daytime in a 

multitude of ha scopes , they’re just great.

NGC 1502 ... Ed are you still using 

an SV/SF 50 ?

brian 

[Steve Clay]

The OVL zoom is reall good.

[Louis D]

19 minutes ago, Steve Clay said:

The OVL zoom is reall good.

Unless you need to wear eyeglasses at the eyepiece due to strong astigmatism.  I measured mine to have between 9mm and 11mm of usable eye relief making the already narrow AFOV (33 to 49 degrees) even narrower.

[johninderby]

The TS zoom has 15mm eye relief and 40 to 53 degrees so perhaps not quite the same as the OVL after all.

[bomberbaz]

1 hour ago, Louis D said:

Unless you need to wear eyeglasses at the eyepiece due to strong astigmatism.  I measured mine to have between 9mm and 11mm of usable eye relief making the already narrow AFOV (33 to 49 degrees) even narrower.

I do have astigmatism but find that once the exit pupil is less than 3mm it no longer causes a serious issue, therefore I do without my glasses. 

I have found this out after a long time of ignoring many eyepieces due to low eye relief, now I know better. You should try higher powered EP without your glasses, you may be surprised.

Anyway, I have ordered the OVL as it offers all I require of it at the right price.

Thanks to all for their input, much obliged as always.

Steve

Edited April 14, 2020 by bomberbaz

[Louis D]

51 minutes ago, bomberbaz said:

I do have astigmatism but find that once the exit pupil is less than 3mm it no longer causes a serious issue, therefore I do without my glasses. 

I have found this out after a long time of ignoring many eyepieces due to low eye relief, now I know better. You should try higher powered EP without your glasses, you may be surprised.

Anyway, I have ordered the OVL as it offers all I require of it at the right price.

Thanks to all for their input, much obliged as always.

Steve

I have 2 diopters of astigmatism, and I can indeed get away without using eyeglasses at sub-1mm exit pupils, but there is still some minor improvement even then when I swap in my eyeglasses.  Once I get below 0.7mm exit pupil, floaters become a huge issue for me, so I have a narrow window of opportunity not to wear eyeglasses.  According to TV's Dioptrx chart below, you must have about 0.75x diopters of astigmatism.

[Paul73]

I’ve been very impressed with the Baader mk III and MkIV. Had one for white light and one for HA! But, these are the only zooms that I have tried. 

Paul

[bomberbaz]

 

8 minutes ago, Louis D said:

I have 2 diopters of astigmatism, and I can indeed get away without using eyeglasses at sub-1mm exit pupils, but there is still some minor improvement even then when I swap in my eyeglasses.  Once I get below 0.7mm exit pupil, floaters become a huge issue for me, so I have a narrow window of opportunity not to wear eyeglasses.  According to TV's Dioptrx chart below, you must have about 0.75x diopters of astigmatism.

Actually just checked my latest script and its 1.5, they did advise me this has changed a little. So according to that I should be getting issues right down to 1.5mm. However like I said I seem to find it ok below 3mm.

I think though given the above chart and my latest script some additional testing is required.  Perhaps my need has changed without me realising, we will see.

Cheers Louis 👍

[NGC 1502]

11 hours ago, Solar B said:

NGC 1502 ... Ed are you still using 

an SV/SF 50 ?

Hi Brian, sorry only just seen your question.  I’ve not tried  a SV/SF 50.  The Solarscope 50 from Isle of Man is owned by my local club and I’ve used it lots of times.  Great build quality.  Views of prominencies were on par with the other Ha scopes, but where it pulled ahead was disc detail. Also the view is not cramped, and the sweet spot large.

Don’t know if you needed that info but thought I’d include it. If you need further please ask.

Ed.

[Solar B]

Thanks Ed and Understood , the stand alone solarscopes are SV (solar view) the filters & 

BFs are SF (solar filter) , I think your referring to an SV50 which I also had some years 

ago it's one of those I regret selling as the finesse of their etalons are unsurpassed ie a 

SS filter will often outperform  DS configurations from other manufacturers.

Brian 

Edited April 14, 2020 by Solar B