Antares region and Rho Ophiuchi

[Alfredo Beltran]

Hi

This is my first image of wide field with lenses. I chose the Antares Nebula and Rho Ophiuchi region.

The integration time is 4hr 3 min (41 x 3 min at ISO 400). The lens is a EF-S 55-250 mm IS at 90 mm and f4.5 with the 2" IDAS D1 filter. Camera is a modified T1i piggy back mounted on a C925 EdgeHD used on an iEQ45 mount.

To use the 2" filter with an EF-S lens I used a step down ring from 58 to 48 mm, so the filter was in front of the lens.

Captured with Backyard EOS and processed completely in Pixinsight.

Thanks for watching!

Best regards,

Alfredo

[dts350z]

I'd like to do something similar with my Tamaron 28-300mm (except the filter size is 67mm).

 

Where did you get the step down ring?

 

In camera filter terms, what do people call the 2"dia M48 thread?

 

Thanks,

Z

 

 

[Alfredo Beltran]

Hi Z

 

The 2" filter is one of the standard sizes used in astronomy. It has a clear aperture of 48 mm.

 

I got the step down ring from Amazon. It only costed around 5 dollars.

 

With my EF-S 18-135, which as your lens has an aperture of 67 mm, the step down ring causes severe vignetting. Be careful with that.

 

Best regards

 

Alfredo

[dts350z]

Yeah I understand the 2 inch filter spec. I just don't see any step down rings that mention "2 inch, M48". They only talk about the filter size. 2" is actually 50.8 mm so is that a 52mm filter, and does a 52mm filter have the right M48 thread?

 

Wikipedia says:

 

 

Threaded round filters[edit]

The most common standard filter sizes for circular filters include 30.5 mm, 37 mm, 40.5 mm, 43 mm, 46 mm, 49 mm, 52 mm, 55 mm, 58 mm, 62 mm, 67 mm, 72 mm, 77 mm, 82 mm, 86 mm, 95 mm, 112 mm and 127 mm. Other filter sizes within this range may be hard to find since the filter size may be non-standard or may be rarely used on camera lenses. The specified diameter of the filter in millimeters indicates the diameter of the male threads on the filter housing. The thread pitch is 0.5 mm, 0.75 mm or 1.0 mm, depending on the ring size. A few sizes (e.g. 30.5 mm) come in more than one pitch.

Filter diameter for a particular lens is commonly identified on the lens face by the mathematical symbol ⌀ (this symbol is distinct from the Scandinavian Latin letter Ø, the Greek letter Φ, the Cyrillic letter Ф, the empty set symbol∅, and the slashed zero glyph 0̸). For example, a lens marking may indicate: “⌀55mm”.

 

but that doesn't tell me if the one of those matches the 2" M48.

 

 

 

 

 

[Alfredo Beltran]

For this image I used the 58 to 48 mm step down ring. And the 2" filter on top fits perfectly.

 

You will enjoy that setup!

 

Regards

 

Alfredo

 

 

[Alfredo Beltran]

One more thing: since there is no 67 to 48 mm step down ring, I used the 67 to 58 and then the 58 to 48 for testing. It shows vignetting at some lens' apertures.

 

Regards

 

Alfredo