Delos 3.5 or 4.5 ? if any..

[allen g]

My scope is np 101. As for the higher end of EPs I have the 10 ethos and 6 delos and have the tv 2x barlow which gives me 10mm, 6mm, 5mm & 3mm. All work fine including 3mm so far. Would a 3.5 or 4.5 be better to fill in or is either unnecessary. I tried the 3.7 ethos which is fine but 110 degrees at $ 650 is probably not necessary at all because magnification of this level would only be good for planets and the moon. thanks in advance for feedback. allen g

[allen g]

I should mention that I tried the tv 3-6 zoom however I enjoy wide field views and use the Discmount which is an Az-Alt so field is somewhat important.

[Stu]

Both would be lovely in it I'm sure. If I'm correct, your focal length is 540mm giving you either x120 or x154. I guess I'd be tempted by the higher power of the 3.5 on planets, but then again having x120 and x240 with the Barlow might be quite nice :-)

Stu

[John]

Although I've yet to use a Delos, I do use the 3.5mm and 5mm Pentax XW's which are reputed to be every similar to the Delos. My shortest FL scope is my Vixen ED102SS which is an F/6.5 so slightly slower than your NP101. I also use Radian's at 4mm and 3mm with the scope and an Ethos at 6mm. All of these get used lots.

For max field (which I love as well !) and, no aberrations whatsoever and the security of a 2" fitting I can also highly recommend the Powermate 2" 2x. That would give you a 5mm Ethos and a 3mm Delos with absolutely no side effects apart from the weight, which the focuser of the NP101 should be well up to.

[Stu]

The TV101 is f5.4 so a fair bit faster and a 3mm 'only' gives x180 vs x220ish for your Vixen. I guess I would be wanting a little more mag to exploit the scope to its maximum. Possibly even a 2.5 type 6 would be nice at x216

Stu

[John]

The TV101 is f5.4 so a fair bit faster and a 3mm 'only' gives x180 vs x220ish for your Vixen. I guess I would be wanting a little more mag to exploit the scope to its maximum. Possibly even a 2.5 type 6 would be nice at x216

Stu

Thats true Stu - If my Vixen can usefully use 220x then I'm sure an NP101 will too

[Stu]

Yep, I treat x230 as a normal maximum with good conditions on my 106mm so am sure the TV101 would be fine at those levels too

[alan potts]

I have both you are thinking of but I have not had enough time with the 3.5mm to comment, it looks as good as you would think it would be with Saturn. The 4.5mm is excellent and there is a review on this by in Equipment.

As you seem to be happy with barlowed focal lenghts, and there is nothing wrong with that, what about the Delos 8mm and that would barlow to 4mm ( sorry for stating the obvious ).

If you had your heart set on one of the two you mention, I would go for the 4.5mm as I think it will get more scope time.

Alan.

[allen g]

thoughtful feedback I thank you. I wonder how often the skies would be suitable to go beyond 180 in the NP 101. I assume high magnification would only be good for the moon and planets, albeit I am very curious what the views would be like in the 200 - 250x range. I had a fleeing thought about the 2.5 but realistically how often would it be used not to mention the low eye relief (I prefer 15 & 20) The notion of getting the delos 8mm is intriguing. In line with the other EPs I have along with the barlow would give me 3, 4, 5 (with barlow) and 6, 8, 10 without the barlow. I wonder if that would do it at the useable high range. I can also use the 8 in my meade 8" LX 90 as well when conditions are good (the 6 even worked well periodically). Appreciate your thoughts as to this approach.

[alan potts]

Allen,

Most of, if not all of, my top end F/L get used in the 115mm APO which will have a performance just a little better tha yours with it being bigger. Your scope is a top line scope don't forget. I have just bought the 3.5mm only because of the discount that is on at the moment. The 3.5 on mine gives around X230 and because of that it will not get used as much as the 4mm Radian I have giving X201. I think it is a shame that the Delos range does not have a 5mm, 4mm and 3mm. for me the 4mm is what you would get the most use from, though the Radian is excellent and John also uses one of these now and I understand likes it. Up at these magnifcations FOV is very nice but not so important to me, I also have the Nagler zoom filling the in the gaps from 6-3mm. I do not have the 8mm but I am sure having had most of the others it is very good indeed.

Alan

[Stu]

I quite regularly use x197 in my 106 triplet, and occasionally x230. It depends on your favoured targets but at x180 I think you are leaving something on the table for your scope on good nights for planetary observing.

Given your eye relief preferences, the Delos makes sense, and probably the 4.5mm would best for DSOs. That still leaves option of barlowing ( or potentially a PowerMate) for x240 for those really cracking nights and for Mars for instance. Sure the scope can take it if the skies are good.

You'd get plenty of use out of the 4.5mm I reckon

Stu

[allen g]

thanks for all the feedback. I just picked up the delos 8 mm now I have at higher end starting with 10 ethos, 8 & 6 delos and with barlow 5, 4, & 3

Good line up in this range. Furthermore can use the 8 in my meade 8" lx 90 as well so 8 would get more use. If I see that can go higher than 3 next stop possible nagler 2.5, albeit ER is not that high.

[alan potts]

That's pretty much the same line-up I have but with slightly different eyepieces from other TV ranges but all quality. I stand to be corrected but I don't think you can do a great deal better than that, I have had the 10mm and the 6mm so I know how good they are, still not sure that going to Ethos was the right call for me but it is too late now, hadly ended up with rubbish.

So many congratlations on your new 8mm I hope my suggestion works for you, they barlow of powermater so well.

Just another suggestion, consider the 5mm Pentax XW as a stand alone 5mm, which will Barlow to 2.5mm, I can't see a better 5mm on the market.

Alan