Eyepieces for f4.7 dob

[Mike_S]

Do most people prefer twist or soft eyecups? I don’t wear glasses. I have only the soft ones. Those Myrids are discontinued but FLO still have them in 3.5, 5 and 9mm. Quite a lot Cheaper too than the APM’s with £159-£166 rather than €230-235 plus shipping.

[bingevader]

21 minutes ago, alanjgreen said:

The Lunt/APM are better.

How so?

Can you elaborate please?

Cheaper, definitely.

They're the same glass as the Myriads which were comparable to the ES.

[alanjgreen]

3 minutes ago, bingevader said:

How so?

Can you elaborate please?

Cheaper, definitely.

They're the same glass as the Myriads which were comparable to the ES.

You must have read different reviews to the ones I read on cloudynights. The lunts/APMs are the same, the other clones are not the same (or so I have read several times).

At the end of the day, buy whatever floats your boat.

[bingevader]

I was just hoping you'd enlighten us.

Do you have any and can you tell us why they are better please?

I haven't done an extensive search, but the couple that came up on CoudyNights seem to think they were clones too!

Also, the thread relating to them on here.

People come here for advice, predominantly based on experience.

If you have experience of these EPs and why they are better please tell us.

If not, and you've 2nd hand knowledge from elsewhere then just post the link.

I just want to know why they are better.

I used to have a boat, but found it floated best on water. ?

[Charic]

4 hours ago, MSammon said:

It’s just so i can keep it in the eyepiece easier

That makes sense. Tracking smoothly does take practice, but give it time, it soon becomes second nature. 

[bingevader]

That's part of the reason for my slow move to 82° EPs.

The added drift time does make a big difference.

Hence my questions about these Lunt EPs.

If these clones are as good as or better than the likes of ES, at a lower price, I'll definitely consider adding one to the Christmas list!

[Mike_S]

Shame the OVL ones are discontinued. They look great value. 

[Louis D]

2 hours ago, bingevader said:

How so?

Can you elaborate please?

Cheaper, definitely.

They're the same glass as the Myriads which were comparable to the ES.

If you hunt around on CN, you'll find reviews like this one that repeatedly gives the win to the HDCs over the ES-100s.  IIRC, the 9mm is a near draw between the two lines.  The HDCs are nicer in the shorter focal lengths because you can use them in either 1.25" or 2" mode with the thread-on 2" adapter unlike the ES which are 2"-only.  They are also significantly lighter than the ES-100s.  The Lunt/APM are nicer than the Myriad/WO versions because of the tapered top.  That broad top requires you to tip your head to get your eye in close.

[John]

Personally I would go for the Lunt HDC style eyecups over the more rigid twist up ones that the Myriads have. When I did the comparison with my Ethos eyepieces I found the flexible eye cups that the Ethos have more comfortable to use than the Myriad ones. 

I'm not sure whether the optics inside the Lunt HDC's are the same as those inside the Myriads or not. Without taking them apart and comparing the lens arrangements, spacing, curvature etc, etc. it's virtually impossible to tell IMHO.

Also remember that 100 degree eyepieces are large and heavy and may affect the balance of your scope. This can be dealt with of course but it's worth being aware of it.

Do think about a coma corrector for your F/4.7 newtonian as well. 100 degree eyepieces are showing a lot of off-axis field and thats where the coma lurks.

 

 

[Mike_S]

Thanks. If it throws it out of balance, how do I correct that with a dob? Well what’s the easiest way?

[John]

1 minute ago, MSammon said:

Thanks. If it throws it out of balance, how do I correct that with a dob? Well what’s the easiest way?

Add some weight to the bottom end of the tube if the imbalance is too much for the friction knobs on the altitude axis to handle. I use a magnetic knife rack on the bottom end of my 12" dob with a couple of iron weights which I switch around depending on the eyepiece that I'm using:

 

[Mike_S]

I’ve got springs that hook onto the supports from the mount, do they help with this?

[John]

20 minutes ago, MSammon said:

I’ve got springs that hook onto the supports from the mount, do they help with this?

Up to a point, yes, but a 20mm 100 degree eyepiece weighs around 1kg so quite a weight at the top end of the tube. When you are observing targets close to the zenith there is no problem but as the elevation of the scope drops the additional weight at the front end makes itself felt more and more so thats when you may need to add counterweighting to the back end.

[Louis D]

2 hours ago, John said:

When you are observing targets close to the zenith there is no problem

Except for Dobson's hole which I haven't heard mentioned in forever.  Whenever I get an object passing through zenith, I get really cranky twisting and pushing my Dob trying to manually track it.  It's times like those that I wish I had a PortaBall scope.

[John]

11 minutes ago, Louis D said:

Except for Dobson's hole which I haven't heard mentioned in forever.  Whenever I get an object passing through zenith, I get really cranky twisting and pushing my Dob trying to manually track it.  It's times like those that I wish I had a PortaBall scope.

Yes, it can be awkward tracking at or near the zenith with a dob.

 

[DRT]

APM/Lunt v Myriad - I have experience of both. The Myriad stayed in my case for about three weeks due to the inferior eyecup, which just wasn't comfortable for me to use. I have no idea whether or not the glass is the same and I didn't have one of each in the same focal length but overall the Lunt/APM version is much more comfortable to use.

[bingevader]

18 hours ago, Louis D said:

If you hunt around on CN, you'll find reviews like this one that repeatedly gives the win to the HDCs over the ES-100s.  IIRC, the 9mm is a near draw between the two lines.  The HDCs are nicer in the shorter focal lengths because you can use them in either 1.25" or 2" mode with the thread-on 2" adapter unlike the ES which are 2"-only.  They are also significantly lighter than the ES-100s.  The Lunt/APM are nicer than the Myriad/WO versions because of the tapered top.  That broad top requires you to tip your head to get your eye in close.

Thanks.

[Mike_S]

Do you think I should be able to use the 5mm on planets most clear nights in the U.K. with a 10 inch F4.7 in a town centre? Shows up as orange on light pollution maps but not red.

[alanjgreen]

48 minutes ago, MSammon said:

Do you think I should be able to use the 5mm on planets most clear nights in the U.K. with a 10 inch F4.7 in a town centre? Shows up as orange on light pollution maps but not red.

The 5mm size is a good match for your scope producing a near 1mm exit pupil (5/4.7).

However, if your key interest is planets then the x240 is probably a little too much for Jupiter and maybe Saturn too on most nights.

It will be fine on Mars which never gives a sharp focused view anyway (x300 is great for mars).

I would be looking closer to x200 for Saturn and maybe a little less for Jupiter. There is plenty to see on Jupiter so having the sharpest possible view is important.

Really, there is no single eyepiece that's does all the planets. On any night you need to hunt for the best magnification by trial and error.

Jupiter has passed its best for this year so you could ignore it for now. Saturn is viewable and so too is Mars.

If your total budget is £200 then you may be better buying a spread of cheaper eyepieces then you have more chance with the planets. Try to get 6mm, 7mm and 8mm covered (x200, x171, x150). 

See what you can find second hand then you can move them on should you want to replace them in the future. 

If you want to blow the lot on one eyepiece then probably the 9mm is the better choice as with x133 it will be useable every night. No point paying big money for an eyepiece that sits in your case. Target the fringe eyepieces later...

Alan

5mm and 8mm here

http://www.astrobuysell.com/uk/propview.php?view=140223

Then add a 6.7mm ES 82 degree to fill the gap in-between?

[Ricochet]

28 minutes ago, MSammon said:

Do you think I should be able to use the 5mm on planets most clear nights in the U.K. with a 10 inch F4.7 in a town centre? Shows up as orange on light pollution maps but not red.

(Visible) light pollution makes no difference to the maximum magnification you can use, only the minimum (due to sky brightness). What does make a difference is heat being released into the atmosphere. Man made structures tend to release heat later into the night than vegetation and this heat causes atmospheric turbulence and this will limit your maximum magnification. To limit the effect of this local turbulence you should try to observe over vegetation if possible, or roads in preference to houses. Even observing something as it passes over the gap between two houses can show an improvement.

I have the same focal length scope and so to add to Alan's advice regarding the individual planets I would say that an 8mm should be useable every night, a 7mm most nights, a 6mm often and a 5mm some of the time. Of course this will depend on the local conditions and you may find your location to have different limits.

[bingevader]

You'll probably end up getting a range of short focal length eyepieces.

As you've probably noticed, at the shorter focal lengths there's quite a dramatic difference in magnification between eyepieces.

But I wouldn't rush at it, as with the others, take your time and find a range or design you are most comfortable with.

[Mike_S]

Amazing advice thanks. Yes at the moment I’m so occupied on the planets and learning the basics of getting the most out of my scope then I have the turn left at Orion book to start looking at dso’s But for now I want to improve on what I have been getting. Wide view still very appealing to help keep the planets in range. It’s difficult being a beginner and not wanting to waste money when I’m not sure what I want so I am very grateful for the learning. I couldn’t press a button to order a £300 eyepiece when there is lots of improvements I could try for less. I could increase budget to £250 to get an APM. Wife is okay with it too as long as I get the kitchen finished in ours by October lol.  I now have some starting points whether it’s a few cheaper BST’s or try a more expensive 82 or 100 degree. Will just keep adding little by little as I learn what I need. 

[Mike_S]

Sorry to bring this up again but does anybody know for sure what focal ratio the APM/Myriad/Lunt are corrected to? After more observing I’m trying to decide between Pentax XW that are corrected to F4 and Myriad 100/110 degree.